WorldWideScience

Sample records for high efficiencygreen light

  1. High efficiency incandescent lighting

    Science.gov (United States)

    Bermel, Peter; Ilic, Ognjen; Chan, Walker R.; Musabeyoglu, Ahmet; Cukierman, Aviv Ruben; Harradon, Michael Robert; Celanovic, Ivan; Soljacic, Marin

    2014-09-02

    Incandescent lighting structure. The structure includes a thermal emitter that can, but does not have to, include a first photonic crystal on its surface to tailor thermal emission coupled to, in a high-view-factor geometry, a second photonic filter selected to reflect infrared radiation back to the emitter while passing visible light. This structure is highly efficient as compared to standard incandescent light bulbs.

  2. High Brightness OLED Lighting

    Energy Technology Data Exchange (ETDEWEB)

    Spindler, Jeffrey [OLEDWorks LLC; Kondakova, Marina [OLEDWorks LLC; Boroson, Michael [OLEDWorks LLC; Hamer, John [OLEDWorks LLC

    2016-05-25

    In this work we describe the technology developments behind our current and future generations of high brightness OLED lighting panels. We have developed white and amber OLEDs with excellent performance based on the stacking approach. Current products achieve 40-60 lm/W, while future developments focus on achieving 80 lm/W or higher.

  3. High Intensity Lighting

    Science.gov (United States)

    1982-01-01

    Nightime illumination is an important part of round-the-clock pre-launch preparations because NASA uses TV and film cameras to monitor each step of the preliminaries and at times to identify the cause of malfunction during countdown. Generating a one billion candlepower beam visible 50 miles away, the lamps developed by Duro-Test Corporation provide daylight quality light that eliminates color distortion in film and TV coverage. The lighting system was first used at Kennedy Space Center in 1968 for the launch of Apollo 8. Modified versions are available in wide range of applications, such as the battery of spotlights with colored filters that light up Niagara Falls, as well as the lamps used in the projectors for the Smithsonian's IMAX Theatre, indoor theatres with supersized screens and outdoor projection systems.

  4. Strategy Guideline: High Performance Residential Lighting

    Energy Technology Data Exchange (ETDEWEB)

    Holton, J.

    2012-02-01

    The Strategy Guideline: High Performance Residential Lighting has been developed to provide a tool for the understanding and application of high performance lighting in the home. The high performance lighting strategies featured in this guide are drawn from recent advances in commercial lighting for application to typical spaces found in residential buildings. This guide offers strategies to greatly reduce lighting energy use through the application of high quality fluorescent and light emitting diode (LED) technologies. It is important to note that these strategies not only save energy in the home but also serve to satisfy the homeowner's expectations for high quality lighting.

  5. Strategy Guideline. High Performance Residential Lighting

    Energy Technology Data Exchange (ETDEWEB)

    Holton, J. [IBACOS, Inc., Pittsburgh, PA (United States)

    2012-02-01

    This report has been developed to provide a tool for the understanding and application of high performance lighting in the home. The strategies featured in this guide are drawn from recent advances in commercial lighting for application to typical spaces found in residential buildings. This guide offers strategies to greatly reduce lighting energy use through the application of high quality fluorescent and light emitting diode (LED) technologies. It is important to note that these strategies not only save energy in the home but also serve to satisfy the homeowner’s expectations for high quality lighting.

  6. Light and Light Sources High-Intensity Discharge Lamps

    CERN Document Server

    Flesch, Peter G

    2006-01-01

    Light and Light Sources gives an introduction to the working principles of high-intensity discharge (HID) lamps and points out challenges and problems associated with the development and operation of HID lamps. The state-of-the-art in electrode and plasma diagnostics as well as numerical methods used for the understanding of HID lamps are described. This volume addresses students as well as scientists and researchers at universities and in industry.

  7. High-transmission electrowetting light valves

    Science.gov (United States)

    Heikenfeld, J.; Steckl, A. J.

    2005-04-01

    High-efficiency spatial light modulation has been demonstrated for transmissive electrowetting (EW) light valves (ELVs). The ELV structure consists of a competitive oil/water-on-dielectric EW cell fabricated on an optically transparent substrate. ELVs are configured as display devices by attaching a diffuse backlight powered by white converted InGaN light emitting diodes. The oil film contains ˜1wt.% nonpolar organic chromophores which absorb with near-neutral optical density across the visible light spectrum. Using the EW effect, spatial light modulation is achieved as the water layer locally displaces the oil film. The transmissivity of the cell can be modulated from ˜5% (zero bias) to >80% (˜30V). ELV switching speed depends on cell size, typically ˜10-100ms for 1 and 3mm2 cells. Additional optical enhancement can decrease the off-state ELV transmissivity to <1%.

  8. High-Energy Compton Scattering Light Sources

    CERN Document Server

    Hartemann, Fred V; Barty, C; Crane, John; Gibson, David J; Hartouni, E P; Tremaine, Aaron M

    2005-01-01

    No monochromatic, high-brightness, tunable light sources currently exist above 100 keV. Important applications that would benefit from such new hard x-ray sources include: nuclear resonance fluorescence spectroscopy, time-resolved positron annihilation spectroscopy, and MeV flash radiography. The peak brightness of Compton scattering light sources is derived for head-on collisions and found to scale with the electron beam brightness and the drive laser pulse energy. This gamma 2

  9. High accuracy & long timescale light curves

    Directory of Open Access Journals (Sweden)

    Hodgkin S.

    2013-04-01

    Full Text Available We present a theoretical analysis of the optical light curves (LCs for short-period high-mass transiting extrasolar planet systems. Our method considers the primary transit, the secondary eclipse, and the overall phase shape of the LC between the occultations. Phase variations arise from (i reflected and thermally emitted light by the planet, (ii the ellipsoidal shape of the star due to the gravitational pull of the planet, and (iii the Doppler shift of the stellar light as the star orbits the center of mass of the system. Our full model of the out-of-eclipse variations contains information about the planetary mass, orbital eccentricity, the orientation of periastron and the planet's albedo. For a range of hypothetical systems we demonstrate that the ellipsoidal variations (ii. can be large enough to be distinguished from the remaining components and that this effect can be used to constrain the planet's mass. As an example we presend KOI-13b (candidate exoplanet system included in the September 2011 Kepler data release. The Kepler light curve shows both primary and secondary eclipses, as well as significant out-of-eclipse light curve variations. We model the relative contributions from (i thermal emission from the companion, (ii planetary reflected light, (iii doppler beaming, and (iv ellipsoidal variations in the host-star arising from the tidal distortion of the host star by its companion. Our analysis, based on the light curve alone, enables us to constrain the mass of the KOI-13.01 companion to be MC = 8.3 ± 1.25 MJ and thus demonstrates that the transiting companion is a planet. The teqnique is useful for current and future space missions such as Kepler and PLATO.

  10. High accuracy & long timescale light curves

    Science.gov (United States)

    Mislis, D.; Hodgkin, S.

    2013-04-01

    We present a theoretical analysis of the optical light curves (LCs) for short-period high-mass transiting extrasolar planet systems. Our method considers the primary transit, the secondary eclipse, and the overall phase shape of the LC between the occultations. Phase variations arise from (i) reflected and thermally emitted light by the planet, (ii) the ellipsoidal shape of the star due to the gravitational pull of the planet, and (iii) the Doppler shift of the stellar light as the star orbits the center of mass of the system. Our full model of the out-of-eclipse variations contains information about the planetary mass, orbital eccentricity, the orientation of periastron and the planet's albedo. For a range of hypothetical systems we demonstrate that the ellipsoidal variations (ii.) can be large enough to be distinguished from the remaining components and that this effect can be used to constrain the planet's mass. As an example we presend KOI-13b (candidate exoplanet system) included in the September 2011 Kepler data release. The Kepler light curve shows both primary and secondary eclipses, as well as significant out-of-eclipse light curve variations. We model the relative contributions from (i) thermal emission from the companion, (ii) planetary reflected light, (iii) doppler beaming, and (iv) ellipsoidal variations in the host-star arising from the tidal distortion of the host star by its companion. Our analysis, based on the light curve alone, enables us to constrain the mass of the KOI-13.01 companion to be MC = 8.3 ± 1.25 MJ and thus demonstrates that the transiting companion is a planet. The teqnique is useful for current and future space missions such as Kepler and PLATO.

  11. Pupillary light reaction during high altitude exposure.

    Directory of Open Access Journals (Sweden)

    Maximilian Schultheiss

    Full Text Available PURPOSE: This study aimed to quantify the pupillary light reaction during high altitude exposure using the state of the art Compact Integrated Pupillograph (CIP and to investigate a potential correlation of altered pupil reaction with severity of acute mountain sickness (AMS. This work is related to the Tübingen High Altitude Ophthalmology (THAO study. METHODS: Parameters of pupil dynamics (initial diameter, amplitude, relative amplitude, latency, constriction velocity were quantified in 14 healthy volunteers at baseline (341 m and high altitude (4559 m over several days using the CIP. Scores of AMS, peripheral oxygen saturation and heart rate were assessed for respective correlations with pupil dynamics. For statistical analysis JMP was used and data are shown in terms of intra-individual normalized values (value during exposure/value at baseline and the 95% confidence interval for each time point. RESULTS: During high altitude exposure the initial diameter size was significantly reduced (p<0.05. In contrast, the amplitude, the relative amplitude and the contraction velocity of the light reaction were significantly increased (p<0.05 on all days measured at high altitude. The latency did not show any significant differences at high altitude compared to baseline recordings. Changes in pupil parameters did not correlate with scores of AMS. CONCLUSIONS: Key parameters of the pupillary light reaction are significantly altered at high altitude. We hypothesize that high altitude hypoxia itself as well as known side effects of high altitude exposure such as fatigue or exhaustion after ascent may account for an altered pupillogram. Interestingly, none of these changes are related to AMS.

  12. High Quantum Efficiency OLED Lighting Systems

    Energy Technology Data Exchange (ETDEWEB)

    Shiang, Joseph [General Electric (GE) Global Research, Fairfield, CT (United States)

    2011-09-30

    The overall goal of the program was to apply improvements in light outcoupling technology to a practical large area plastic luminaire, and thus enable the product vision of an extremely thin form factor high efficiency large area light source. The target substrate was plastic and the baseline device was operating at 35 LPW at the start of the program. The target LPW of the program was a >2x improvement in the LPW efficacy and the overall amount of light to be delivered was relatively high 900 lumens. Despite the extremely difficult challenges associated with scaling up a wet solution process on plastic substrates, the program was able to make substantial progress. A small molecule wet solution process was successfully implemented on plastic substrates with almost no loss in efficiency in transitioning from the laboratory scale glass to large area plastic substrates. By transitioning to a small molecule based process, the LPW entitlement increased from 35 LPW to 60 LPW. A further 10% improvement in outcoupling efficiency was demonstrated via the use of a highly reflecting cathode, which reduced absorptive loss in the OLED device. The calculated potential improvement in some cases is even larger, ~30%, and thus there is considerable room for optimism in improving the net light coupling efficacy, provided absorptive loss mechanisms are eliminated. Further improvements are possible if scattering schemes such as the silver nanowire based hard coat structure are fully developed. The wet coating processes were successfully scaled to large area plastic substrate and resulted in the construction of a 900 lumens luminaire device.

  13. COP1/SPA ubiquitin ligase complexes repress anthocyanin accumulation under low light and high light conditions.

    Science.gov (United States)

    Maier, Alexander; Hoecker, Ute

    2015-01-01

    In Arabidopsis and many other plant species, anthocyanin pigments accumulate only after light exposure and not in darkness. Excess light of very high fluence rates leads to a further, very strong increase in anthocyanin levels. How excess light is sensed is not well understood. Here, we show that mutations in the key repressor of light signaling, the COP1/SPA complex, cause a strong hyperaccumulation of anthocyanins not only under normal light but also under excess, high light conditions. Hence, normal light signaling via COP1/SPA is required to prevent hyperaccumulation of anthocyanins under these high light conditions. However, since cop1 and spa mutants show a similar high-light responsiveness of anthocyanin accumulation as the wild type it remains to be resolved whether COP1/SPA is directly involved in the high-light response itself.

  14. Injecting Light of High-Power LEDs into Thin Light Guides

    NARCIS (Netherlands)

    Cornelissen, H.J.; Krijn, M.P.C.; Ma, H.; Van Sprang, H.A.

    2010-01-01

    A new method using a thin-film multilayer filter is described to couple light from high-power LEDs into a thin light guide such as an LCD backlight. Light emitted below the critical angle is reflected back to the LED and recycled. Large-angle emitted light passes the filter and is transported by

  15. Injecting light of high-power LEDs into thin light guides

    NARCIS (Netherlands)

    Cornelissen, H.J.; Ho, C.; Ma, H.; Krijn, M.P.C.M.; Van Sprang, H.A.

    2010-01-01

    A new method using a thin-film multilayer filter is described to couple light from high-power LEDs into a thin light guide such as an LCD backlight. Light emitted below the critical angle is reflected back to the LED and recycled. Largeangle emitted light passes the filter and is transported by

  16. Materials for high performance light water reactors

    Science.gov (United States)

    Ehrlich, K.; Konys, J.; Heikinheimo, L.

    2004-05-01

    A state-of-the-art study was performed to investigate the operational conditions for in-core and out-of-core materials in a high performance light water reactor (HPLWR) and to evaluate the potential of existing structural materials for application in fuel elements, core structures and out-of-core components. In the conventional parts of a HPLWR-plant the approved materials of supercritical fossil power plants (SCFPP) can be used for given temperatures (⩽600 °C) and pressures (≈250 bar). These are either commercial ferritic/martensitic or austenitic stainless steels. Taking the conditions of existing light water reactors (LWR) into account an assessment of potential cladding materials was made, based on existing creep-rupture data, an extensive analysis of the corrosion in conventional steam power plants and available information on material behaviour under irradiation. As a major result it is shown that for an assumed maximum temperature of 650 °C not only Ni-alloys, but also austenitic stainless steels can be used as cladding materials.

  17. The Jefferson Lab High Power Light Source

    Energy Technology Data Exchange (ETDEWEB)

    James R. Boyce

    2006-01-01

    Jefferson Lab has designed, built and operated two high average power free-electron lasers (FEL) using superconducting RF (SRF) technology and energy recovery techniques. Between 1999-2001 Jefferson Lab operated the IR Demo FEL. This device produced over 2 kW in the mid-infrared, in addition to producing world record average powers in the visible (50 W), ultraviolet (10 W) and terahertz range (50 W) for tunable, short-pulse (< ps) light. This FEL was the first high power demonstration of an accelerator configuration that is being exploited for a number of new accelerator-driven light source facilities that are currently under design or construction. The driver accelerator for the IR Demo FEL uses an Energy Recovered Linac (ERL) configuration that improves the energy efficiency and lowers both the capital and operating cost of such devices by recovering most of the power in the spent electron beam after optical power is extracted from the beam. The IR Demo FEL was de-commissioned in late 2001 for an upgraded FEL for extending the IR power to over 10 kW and the ultraviolet power to over 1 kW. The FEL Upgrade achieved 10 kW of average power in the mid-IR (6 microns) in July of 2004, and its IR operation currently is being extended down to 1 micron. In addition, we have demonstrated the capability of on/off cycling and recovering over a megawatt of electron beam power without diminishing machine performance. A complementary UV FEL will come on-line within the next year. This paper presents a summary of the FEL characteristics, user community accomplishments with the IR Demo, and planned user experiments.

  18. High Pressure Microwave Powered UV Light Sources

    Science.gov (United States)

    Cekic, M.; Frank, J. D.; Popovic, S.; Wood, C. H.

    1997-10-01

    Industrial microwave powered (*electrodeless*) light sources have been limited to quiescent pressures of 300 Torr of buffer gas and metal- halide fills. Recently developed multi-atmospheric electronegative bu lb fills (noble gas-halide excimers, metal halide) require electric field s for ionization that are often large multiples of the breakdown voltage for air. For these fills an auxiliary ignition system is necessary. The most successful scheme utilizes a high voltage pulse power supply and a novel field emission source. Acting together they create localized condition of pressure reduction and high free electron density. This allows the normal microwave fields to drive this small region into avalanche, ignite the bulb, and heat the plasma to it's operating poin t Standard diagnostic techniques of high density discharges are inapplicable to the excimer bulbs, because of the ionic molecular exci ted state structure and absence of self-absorption. The method for temperature determination is based on the equilibrium population of certain vibrational levels of excimer ionic excited states. Electron d ensity was determined from the measurements of Stark profiles of H_β radiation from a small amount of hydrogen mixed with noble gas and halogens. At the present time, high pressure (Te 0.5eV, ne 3 x 10^17 cm-3) production bulbs produce over 900W of radiation in a 30nm band, centered at 30nm. Similarly, these prototypes when loaded with metal-halide bulb fills produce 1 kW of radiation in 30nm wide bands, centered about the wavelength of interest.

  19. Photocathodes for High Repetition Rate Light Sources

    Energy Technology Data Exchange (ETDEWEB)

    Ben-Zvi, Ilan [Stony Brook Univ., NY (United States). Dept. of Physics and Astronomy. Center for Accelerator Science and Education

    2014-04-20

    This proposal brought together teams at Brookhaven National Laboratory (BNL), Lawrence Berkeley National Laboratory (LBNL) and Stony Brook University (SBU) to study photocathodes for high repetition rate light sources such as Free Electron Lasers (FEL) and Energy Recovery Linacs (ERL). Below details the Principal Investigators and contact information. Each PI submits separately for a budget through his corresponding institute. The work done under this grant comprises a comprehensive program on critical aspects of the production of the electron beams needed for future user facilities. Our program pioneered in situ and in operando diagnostics for alkali antimonide growth. The focus is on development of photocathodes for high repetition rate Free Electron Lasers (FELs) and Energy Recovery Linacs (ERLs), including testing SRF photoguns, both normal-­conducting and superconducting. Teams from BNL, LBNL and Stony Brook University (SBU) led this research, and coordinated their work over a range of topics. The work leveraged a robust infrastructure of existing facilities and the support was used for carrying out the research at these facilities. The program concentrated in three areas: a) Physics and chemistry of alkali-­antimonide cathodes (BNL – LBNL) b) Development and testing of a diamond amplifier for photocathodes (SBU -­ BNL) c) Tests of both cathodes in superconducting RF photoguns (SBU) and copper RF photoguns (LBNL) Our work made extensive use of synchrotron radiation materials science techniques, such as powder-­ and single-­crystal diffraction, x-­ray fluorescence, EXAFS and variable energy XPS. BNL and LBNL have many complementary facilities at the two light sources associated with these laboratories (NSLS and ALS, respectively); use of these will be a major thrust of our program and bring our understanding of these complex materials to a new level. In addition, CHESS at Cornell will be used to continue seamlessly throughout the NSLS dark period and

  20. High Extraction Phosphors for Solid State Lighting

    Energy Technology Data Exchange (ETDEWEB)

    Summers, Chris [Phosphortech Corporation, Kennesaw, GA (United States); Menkara, Hisham [Phosphortech Corporation, Kennesaw, GA (United States); Wagner, Brent [Phosphortech Corporation, Kennesaw, GA (United States)

    2011-09-01

    We have developed high-index, high efficiency bulk luminescent materials and novel nano-sized phosphors for improved solid-state white LED lamps. These advances can potentially contribute to reducing the loss in luminous efficiencies due to scattering, re-absorption, and thermal quenching. The bulk and nanostructured luminescent materials investigated are index matched to GaN and have broad and size-tunable absorption bands, size and impurity tuned emission bands, size-driven elimination of scattering effects, and a separation between absorption and emission bands. These innovations were accomplished through the use of novel synthesis techniques suitable for high volume production for LED lamp applications. The program produced a full-color set of high quantum yield phosphors with high chemical stability. In the bulk phosphor study, the ZnSeS:Cu,Ag phosphor was optimized to achieve >91% efficiency using erbium (Er) and other activators as sensitizers. Detailed analysis of temperature quenching effects on a large number of ZnSeS:Cu,Ag,X and strontium- and calcium-thiogallate phosphors lead to a breakthrough in the understanding of the anti-quenching behavior and a physical bandgap model was developed of this phenomena. In a follow up to this study, optimized phosphor blends for high efficiency and color performance were developed and demonstrated a 2-component phosphor system with good white chromaticity, color temperature, and high color rendering. By extending the protocols of quantum dot synthesis, large nanocrystals, greater than 20 nm in diameter were synthesized and exhibited bulk-like behavior and blue light absorption. The optimization of ZnSe:Mn nanophosphors achieved ~85% QE The limitations of core-shell nanocrystal systems were addressed by investigating alternative deltadoped structures. To address the manufacturability of these systems, a one-pot manufacturing protocol was developed for ZnSe:Mn nanophosphors. To enhance the stability of these material

  1. Highly efficient silicon light emitting diode

    NARCIS (Netherlands)

    Le Minh, P.; Holleman, J.; Wallinga, Hans

    2002-01-01

    In this paper, we describe the fabrication, using standard silicon processing techniques, of silicon light-emitting diodes (LED) that efficiently emit photons with energy around the silicon bandgap. The improved efficiency had been explained by the spatial confinement of charge carriers due to a

  2. High extraction efficiency ultraviolet light-emitting diode

    Science.gov (United States)

    Wierer, Jonathan; Montano, Ines; Allerman, Andrew A.

    2015-11-24

    Ultraviolet light-emitting diodes with tailored AlGaN quantum wells can achieve high extraction efficiency. For efficient bottom light extraction, parallel polarized light is preferred, because it propagates predominately perpendicular to the QW plane and into the typical and more efficient light escape cones. This is favored over perpendicular polarized light that propagates along the QW plane which requires multiple, lossy bounces before extraction. The thickness and carrier density of AlGaN QW layers have a strong influence on the valence subband structure, and the resulting optical polarization and light extraction of ultraviolet light-emitting diodes. At Al>0.3, thinner QW layers (<2.5 nm are preferred) result in light preferentially polarized parallel to the QW plane. Also, active regions consisting of six or more QWs, to reduce carrier density, and with thin barriers, to efficiently inject carriers in all the QWs, are preferred.

  3. Using high-power light emitting diodes for photoacoustic imaging

    DEFF Research Database (Denmark)

    Hansen, René Skov

    The preliminary result of using a high-power light emitting diode, LED, for photoacoustic imaging is presented. The pulsed light source is created by a 1Watt red Luxeon LED. The LED delivers light pulses with 25W peak power when supplied by 40A peak, 60ns wide current pulses. The phantom used...... for the experiment consists of a 3mm high x 5mm wide slice of green colored gelatine overlaid by a 3cm layer of colorless gelatine. The light pulses from the LED is focused on the green gelatine. The photoacoustic response from the green gelatine is detected by a single transducer on the opposite (top) surface...

  4. High-flux focusable color-tunable and efficient white-light-emitting diode light engine for stage lighting

    DEFF Research Database (Denmark)

    Chakrabarti, Maumita; Pedersen, Henrik Chresten; Petersen, Paul Michael

    2016-01-01

    colors through a microlens array(MA) at the gate of ∅50 mm. Hence, it produces homogeneous color-mixed tunable white light from 3000 to6000 K that can be adjustable from flood to spot position providing 10% translational loss, whereas the correspondingloss from the halogen–Fresnel spotlight is 37......% and a luminous efficacy of 33 lm∕W are achieved, which is three times higherthan the 2-kW halogen–Fresnel spotlight. In addition to having color rendering of color rendering indexRa > 85 and television lighting consistency index 12 > 70, the dimmable and tunable white light can becolor controlled during......A color mixing light-emitting diode (LED) light engine that can replace 2-kW halogen–Fresnel spotlightwith high-luminous flux in excess of 20,000 lm is reported for applications in professional stage and studio lighting.The light engine focuses and mixes the light from 210 LEDs of five different...

  5. High Output LED-Based Profile Lighting Fixture

    DEFF Research Database (Denmark)

    Török, Lajos; Beczkowski, Szymon; Munk-Nielsen, Stig

    2011-01-01

    Recent developments in power light emitting diode (LED) industry have made LEDs suitable for being efficiently used in high intensity lighting fixtures instead of the commonly used high intensity discharge (HID) lamps. A high output LEDbased profile-light fixture is presented in this paper....... The system consists of a power supply with power factor correction (PFC), a LED-driver and an optical system designed for an overall high efficiency. An interleaved boost converter was chosen as PFC converter. A soft switching phase-shifted full-bridge converter with current doubler provides isolation from...... the grid and delivers the required voltage to the LEDdriver which is a dual interleaved buck converter. Twelve highpower CBT-90 LEDs have been connected in a 4xRGBconfiguration to deliver high output of saturated colors without the need for subtractive color filters. More than 6000 lm of fixture light...

  6. Plant Growth under Natural Light Conditions Provides Highly Flexible Short-Term Acclimation Properties toward High Light Stress

    Science.gov (United States)

    Schumann, Tobias; Paul, Suman; Melzer, Michael; Dörmann, Peter; Jahns, Peter

    2017-01-01

    Efficient acclimation to different growth light intensities is essential for plant fitness. So far, most studies on light acclimation have been conducted with plants grown under different constant light regimes, but more recent work indicated that acclimation to fluctuating light or field conditions may result in different physiological properties of plants. Thale cress (Arabidopsis thaliana) was grown under three different constant light intensities (LL: 25 μmol photons m−2 s−1; NL: 100 μmol photons m−2 s−1; HL: 500 μmol photons m−2 s−1) and under natural fluctuating light (NatL) conditions. We performed a thorough characterization of the morphological, physiological, and biochemical properties focusing on photo-protective mechanisms. Our analyses corroborated the known properties of LL, NL, and HL plants. NatL plants, however, were found to combine characteristics of both LL and HL grown plants, leading to efficient and unique light utilization capacities. Strikingly, the high energy dissipation capacity of NatL plants correlated with increased dynamics of thylakoid membrane reorganization upon short-term acclimation to excess light. We conclude that the thylakoid membrane organization and particularly the light-dependent and reversible unstacking of grana membranes likely represent key factors that provide the basis for the high acclimation capacity of NatL grown plants to rapidly changing light intensities. PMID:28515734

  7. High efficiency lighting: Cost benefit analysis

    Energy Technology Data Exchange (ETDEWEB)

    Di Franco, N. (ENEA, Rome (Italy))

    1992-12-01

    Analysis of the incandescent and fluorescent lamp market in Italy reveals that, by the substitution of conventional equipment with high efficiency lamps, energy savings of up to 3.5 billion kWh could be realized. However, the proper selection of these highly efficient lamps, e.g., compact fluorescent, fluorescent systems using electronic reactors, outdoor systems using sodium or metal iodides, etc., requires a thorough and accurate cost benefit analysis. This article suggests a calculation model for a cost evaluation beginning from the technical and economic aspects of alternative appliances.

  8. High Efficiency Lighting with Integrated Adaptive Control (HELIAC) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed project is the continued development of the High Efficiency Lighting with Integrated Adaptive Control (HELIAC) system. Solar radiation is not a viable...

  9. High Efficiency Lighting with Integrated Adaptive Control (HELIAC) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The innovation of the proposed project is the development of High Efficiency Lighting with Integrated Adaptive Control (HELIAC) systems to drive plant growth. Solar...

  10. Whole high-quality light environment for humans and plants

    Science.gov (United States)

    Sharakshane, Anton

    2017-11-01

    Plants sharing a single light environment on a spaceship with a human being and bearing a decorative function should look as natural and attractive as possible. And consequently they can be illuminated only with white light with a high color rendering index. Can lighting optimized for a human eye be effective and appropriate for plants? Spectrum-based effects have been compared under artificial lighting of plants by high-pressure sodium lamps and general-purpose white LEDs. It has been shown that for the survey sample phytochrome photo-equilibria does not depend significantly on the parameters of white LED light, while the share of phytoactive blue light grows significantly as the color temperature increases. It has been revealed that yield photon flux is proportional to luminous efficacy and increases as the color temperature decreases, general color rendering index Ra and the special color rendering index R14 (green leaf) increase. General-purpose white LED lamps with a color temperature of 2700 K, Ra > 90 and luminous efficacy of 100 lm/W are as efficient as the best high-pressure sodium lamps, and at a higher luminous efficacy their yield photon flux per joule is even bigger in proportion. Here we show that demand for high color rendering white LED light is not contradictory to the agro-technical objectives.

  11. Whole high-quality light environment for humans and plants.

    Science.gov (United States)

    Sharakshane, Anton

    2017-11-01

    Plants sharing a single light environment on a spaceship with a human being and bearing a decorative function should look as natural and attractive as possible. And consequently they can be illuminated only with white light with a high color rendering index. Can lighting optimized for a human eye be effective and appropriate for plants? Spectrum-based effects have been compared under artificial lighting of plants by high-pressure sodium lamps and general-purpose white LEDs. It has been shown that for the survey sample phytochrome photo-equilibria does not depend significantly on the parameters of white LED light, while the share of phytoactive blue light grows significantly as the color temperature increases. It has been revealed that yield photon flux is proportional to luminous efficacy and increases as the color temperature decreases, general color rendering index Ra and the special color rendering index R14 (green leaf) increase. General-purpose white LED lamps with a color temperature of 2700 K, Ra > 90 and luminous efficacy of 100 lm/W are as efficient as the best high-pressure sodium lamps, and at a higher luminous efficacy their yield photon flux per joule is even bigger in proportion. Here we show that demand for high color rendering white LED light is not contradictory to the agro-technical objectives. Copyright © 2017. Published by Elsevier Ltd.

  12. High efficiency III-nitride light-emitting diodes

    Science.gov (United States)

    Crawford, Mary; Koleske, Daniel; Cho, Jaehee; Zhu, Di; Noemaun, Ahmed; Schubert, Martin F; Schubert, E. Fred

    2013-05-28

    Tailored doping of barrier layers enables balancing of the radiative recombination among the multiple-quantum-wells in III-Nitride light-emitting diodes. This tailored doping enables more symmetric carrier transport and uniform carrier distribution which help to reduce electron leakage and thus reduce the efficiency droop in high-power III-Nitride LEDs. Mitigation of the efficiency droop in III-Nitride LEDs may enable the pervasive market penetration of solid-state-lighting technologies in high-power lighting and illumination.

  13. New lighting for the design of high quality biomedical devices

    Science.gov (United States)

    Jaffe, Claudia B.; Jaffe, Steven M.; Conner, Arlie R.

    2009-02-01

    Among the trends redefining 21st century biomedical diagnostics and therapeutics are the advent of low-cost portable analyzers. Because light is a powerful tool in many of today's most widely used life science instruments, high intensity, low cost light engines are essential to the design and proliferation of the newest bioanalytical instruments, medical devices and miniaturized analyzers. The development of new light technology represents a critical technical hurdle in the realization of point-of-care analysis. Lumencor has developed an inexpensive lighting solution, uniquely well suited to the production of safe, effective and commercially viable life science tools and biomedical devices. Lumencor's proprietary, solid-state light engine provides powerful, pure, stable, inexpensive light across the UV-Vis- NIR. Light engines are designed to directly replace the entire configuration of light management components with a single, simple unit. Power, spectral breadth and purity, stability and reliability data will demonstrate the advantages of these light engines for today's bioanalytical needs. Performance and cost analyses will be compared to traditional optical subsystems based on lamps, lasers and LEDs with respect to their suitability as sources for biomedical applications, implementation for development/evaluation of novel measurement tools and overall superior reliability. Next generation products based on such sources will be described to fulfill the demand for portable, hand-held analyzers and affordable devices with highly integrated light sources. A four color violet/cyan/green/red product will be demonstrated. A variety of multicolor prototypes, their spectral outputs and facile modulation will be discussed and their performance capabilities disclosed.

  14. Highly efficient light management for perovskite solar cells

    Science.gov (United States)

    Wang, Dong-Lin; Cui, Hui-Juan; Hou, Guo-Jiao; Zhu, Zhen-Gang; Yan, Qing-Bo; Su, Gang

    2016-01-01

    Organic-inorganic halide perovskite solar cells have enormous potential to impact the existing photovoltaic industry. As realizing a higher conversion efficiency of the solar cell is still the most crucial task, a great number of schemes were proposed to minimize the carrier loss by optimizing the electrical properties of the perovskite solar cells. Here, we focus on another significant aspect that is to minimize the light loss by optimizing the light management to gain a high efficiency for perovskite solar cells. In our scheme, the slotted and inverted prism structured SiO2 layers are adopted to trap more light into the solar cells, and a better transparent conducting oxide layer is employed to reduce the parasitic absorption. For such an implementation, the efficiency and the serviceable angle of the perovskite solar cell can be promoted impressively. This proposal would shed new light on developing the high-performance perovskite solar cells. PMID:26733112

  15. Highly efficient light management for perovskite solar cells

    CERN Document Server

    Wang, Dong-Lin; Hou, Guo-Jiao; Zhu, Zhen-Gang; Yan, Qing-Bo; Su, Gang

    2015-01-01

    Organic-inorganic halide perovskite solar cells have enormous potential to impact the existing photovoltaic industry. As realizing a higher conversion efficiency of the solar cell is still the most crucial task, a great number of schemes were proposed to minimize the carrier loss by optimizing the electrical properties of the perovskite solar cells. Here, we focus on another significant aspect that is to minimize the light loss by optimizing the light management to gain a high efficiency for perovskite solar cells. In our scheme, the slotted and inverted prism structured SiO2 layers are adopted to trap more light into the solar cells, and a better transparent conducting oxide layer is employed to reduce the parasitic absorption. For such an implementation, the efficiency and the serviceable angle of the perovskite solar cell can be promoted impressively. This proposal would shed new light on developing the high-performance perovskite solar cells.

  16. Highly efficient light management for perovskite solar cells

    Science.gov (United States)

    Wang, Dong-Lin; Cui, Hui-Juan; Hou, Guo-Jiao; Zhu, Zhen-Gang; Yan, Qing-Bo; Su, Gang

    2016-01-01

    Organic-inorganic halide perovskite solar cells have enormous potential to impact the existing photovoltaic industry. As realizing a higher conversion efficiency of the solar cell is still the most crucial task, a great number of schemes were proposed to minimize the carrier loss by optimizing the electrical properties of the perovskite solar cells. Here, we focus on another significant aspect that is to minimize the light loss by optimizing the light management to gain a high efficiency for perovskite solar cells. In our scheme, the slotted and inverted prism structured SiO2 layers are adopted to trap more light into the solar cells, and a better transparent conducting oxide layer is employed to reduce the parasitic absorption. For such an implementation, the efficiency and the serviceable angle of the perovskite solar cell can be promoted impressively. This proposal would shed new light on developing the high-performance perovskite solar cells.

  17. Lead paint removal with high-intensity light pulses.

    Science.gov (United States)

    Grapperhaus, Michael J; Schaefer, Raymond B

    2006-12-15

    This paper presents the results of an initial investigation into using high-intensity incoherent light pulses to strip paint. Measurements of light pulse characteristics, the reflectivity of different paints and initial experiments on the threshold for paint removal, and paint removal are presented, along with an approximate model consistent with experimental results. Paint removal tests include lead paint, the reduction of lead levels to below levels required for lead abatement, as well as air and light emissions measurements that are within regulatory guidelines.

  18. Synthesis of aerogel tiles with high light scattering length

    CERN Document Server

    Danilyuk, A F; Okunev, A G; Onuchin, A P; Shaurman, S A

    1999-01-01

    The possibility of aerogel tiles production for RICH detectors is described. Monolithic blocks of silica aerogel were synthesized by two-step sol-gel processing of tetraethoxysilane Si(OEt) sub 4 followed by high temperature supercritical drying with organic solvent. The important characteristic of aerogel is the light scattering length. In the wide range of refraction indexes the light scattering length exceeds 4 cm at 400 nm.

  19. Materials and Designs for High-Efficacy LED Light Engines

    Energy Technology Data Exchange (ETDEWEB)

    Ibbetson, James [Cree, Inc., Durham, NC (United States); Gresback, Ryan [Cree, Inc., Durham, NC (United States)

    2017-09-28

    Cree, Inc. conducted a narrow-band downconverter (NBD) materials development and implementation program which will lead to warm-white LED light engines with enhanced efficacy via improved spectral efficiency with respect to the human eye response. New red (600-630nm) NBD materials could result in as much as a 20% improvement in warm-white efficacy at high color quality relative to conventional phosphor-based light sources. Key program innovations included: high quantum yield; narrow peak width; minimized component-level losses due to “cross-talk” and light scattering among red and yellow-green downconverters; and improved reliability to reach parity with conventional phosphors. NBD-enabled downconversion efficiency gains relative to conventional phosphors yielded an end-of-project LED light engine efficacy of >160 lm/W at room temperature and 35 A/cm2, with a correlated color temperature (CCT) of ~3500K and >90 CRI (Color Rending Index). NBD-LED light engines exhibited equivalent luminous flux and color point maintenance at >1,000 hrs. of highly accelerated reliability testing as conventional phosphor LEDs. A demonstration luminaire utilizing an NBD-based LED light engine had a steady-state system efficacy of >150 lm/W at ~3500K and >90 CRI, which exceeded the 2014 DOE R&D Plan luminaire milestone for FY17 of >150 lm/W at just 80 CRI.

  20. Transmission Lines or Poles, Electric, MDTA High Mast lighting, High Mast Lighting along I 95, Maryland Transportation Authority High Mast Lighting poles, Published in 2011, 1:1200 (1in=100ft) scale, Maryland Transportation Authority.

    Data.gov (United States)

    NSGIC State | GIS Inventory — Transmission Lines or Poles, Electric dataset current as of 2011. MDTA High Mast lighting, High Mast Lighting along I 95, Maryland Transportation Authority High Mast...

  1. Scalable Light Module for Low-Cost, High-Efficiency Light- Emitting Diode Luminaires

    Energy Technology Data Exchange (ETDEWEB)

    Tarsa, Eric [Cree, Inc., Goleta, CA (United States)

    2015-08-31

    During this two-year program Cree developed a scalable, modular optical architecture for low-cost, high-efficacy light emitting diode (LED) luminaires. Stated simply, the goal of this architecture was to efficiently and cost-effectively convey light from LEDs (point sources) to broad luminaire surfaces (area sources). By simultaneously developing warm-white LED components and low-cost, scalable optical elements, a high system optical efficiency resulted. To meet program goals, Cree evaluated novel approaches to improve LED component efficacy at high color quality while not sacrificing LED optical efficiency relative to conventional packages. Meanwhile, efficiently coupling light from LEDs into modular optical elements, followed by optimally distributing and extracting this light, were challenges that were addressed via novel optical design coupled with frequent experimental evaluations. Minimizing luminaire bill of materials and assembly costs were two guiding principles for all design work, in the effort to achieve luminaires with significantly lower normalized cost ($/klm) than existing LED fixtures. Chief project accomplishments included the achievement of >150 lm/W warm-white LEDs having primary optics compatible with low-cost modular optical elements. In addition, a prototype Light Module optical efficiency of over 90% was measured, demonstrating the potential of this scalable architecture for ultra-high-efficacy LED luminaires. Since the project ended, Cree has continued to evaluate optical element fabrication and assembly methods in an effort to rapidly transfer this scalable, cost-effective technology to Cree production development groups. The Light Module concept is likely to make a strong contribution to the development of new cost-effective, high-efficacy luminaries, thereby accelerating widespread adoption of energy-saving SSL in the U.S.

  2. Light emitting diode with high aspect ratio submicron roughness for light extraction and methods of forming

    Science.gov (United States)

    Li, Ting [Ventura, CA

    2011-04-26

    The surface morphology of an LED light emitting surface is changed by applying a reactive ion etch (RIE) process to the light emitting surface. High aspect ratio, submicron roughness is formed on the light emitting surface by transferring a thin film metal hard-mask having submicron patterns to the surface prior to applying a reactive ion etch process. The submicron patterns in the metal hard-mask can be formed using a low cost, commercially available nano-patterned template which is transferred to the surface with the mask. After subsequently binding the mask to the surface, the template is removed and the RIE process is applied for time duration sufficient to change the morphology of the surface. The modified surface contains non-symmetric, submicron structures having high aspect ratio which increase the efficiency of the device.

  3. Light emitting diode with high aspect ratio submicron roughness for light extraction and methods of forming

    Science.gov (United States)

    Li, Ting

    2013-08-13

    The surface morphology of an LED light emitting surface is changed by applying a reactive ion etch (RIE) process to the light emitting surface. High aspect ratio, submicron roughness is formed on the light emitting surface by transferring a thin film metal hard-mask having submicron patterns to the surface prior to applying a reactive ion etch process. The submicron patterns in the metal hard-mask can be formed using a low cost, commercially available nano-patterned template which is transferred to the surface with the mask. After subsequently binding the mask to the surface, the template is removed and the RIE process is applied for time duration sufficient to change the morphology of the surface. The modified surface contains non-symmetric, submicron structures having high aspect ratio which increase the efficiency of the device.

  4. High-resolution interference with programmable classical incoherent light.

    Science.gov (United States)

    Zhang, Er-Feng; Liu, Wei-Tao; Chen, Ping-Xing

    2015-07-01

    A scheme of high-resolution interference with classical incoherent light is proposed. In this scheme, the classical incoherent light is programmable in the amplitude distribution and wavefront, and with the programmable classical incoherent light we improve the resolution of the interference pattern by a factor of 2 compared with the scheme by Erkmen [J. Opt. Soc. Am. A29, 782 (2012)JOAOD60740-323210.1364/JOSAA.29.000782]. Compared with other schemes for observing interference patterns, only single-pixel detection is needed in our proposal. Moreover, the high-resolution interference pattern can be inverted to obtain an image with better resolution compared with that of the scheme proposed by Erkmen. Furthermore, this scheme of high-resolution interference is verified in detail by theoretical analysis and numerical simulations.

  5. High-NOON states by mixing quantum and classical light.

    Science.gov (United States)

    Afek, Itai; Ambar, Oron; Silberberg, Yaron

    2010-05-14

    Precision measurements can be brought to their ultimate limit by harnessing the principles of quantum mechanics. In optics, multiphoton entangled states, known as NOON states, can be used to obtain high-precision phase measurements, becoming more and more advantageous as the number of photons grows. We generated "high-NOON" states (N = 5) by multiphoton interference of quantum down-converted light with a classical coherent state in an approach that is inherently scalable. Super-resolving phase measurements with up to five entangled photons were produced with a visibility higher than that obtainable using classical light only.

  6. High-dimensional quantum channel estimation using classical light

    CSIR Research Space (South Africa)

    Mabena, Chemist M

    2017-11-01

    Full Text Available A method is proposed to characterize a high-dimensional quantum channel with the aid of classical light. It uses a single nonseparable input optical field that contains correlations between spatial modes and wavelength to determine the effect...

  7. High visibility two-photon interference with classical light.

    Science.gov (United States)

    Hong, Peilong; Xu, Lei; Zhai, Zhaohui; Zhang, Guoquan

    2013-06-17

    Two-photon interference with independent classical sources, in which superposition of two indistinguishable two-photon paths plays a key role, is of limited visibility with a maximum value of 50%. By using a random-phase grating to modulate the wavefront of a coherent light, we introduce superposition of multiple indistinguishable two-photon paths, which enhances the two-photon interference effect with a signature of visibility exceeding 50%. The result shows the importance of phase control in the control of high-order coherence of classical light.

  8. Light-Emitting Diodes (LED) for Primary Animal Habitat Lighting in Highly Controlled Environments

    Science.gov (United States)

    Winget, C. M.; Syrkin, N.; Heeke, D.; Mele, G.; Holley, D. C.; Dalton, Bonnie P. (Technical Monitor)

    1996-01-01

    Significant alterations in Biological Clock responses have been reported following sidereal time changes (e.g., Jet-lag), and exposure to microgravity (e.g., daytime sleepiness). Additionally, light reduces circulating melatonin (spectral specificity greatest between 450-500 nm). It was hypothesized that LEDs can replace the current light sources used in zero gravity and terrestrial research laboratories because of their small size, low mass, low energy consumption and long functional life. This report evaluates the capacity of LEDs to entrain the circadian system of rats as judged by measurement of overt behavioral circadian rhythms (activity, feeding, drinking). These data were collected in highly controlled environments similar to the shuttle Animal Enclosure Modules. Two groups were compared: control - animals exposed to standard cool-white fluorescent lights, and test - animals exposed to LEDs with a spectral power distribution matching the fluorescent lights. Gross locomotor activity, feeding and drinking frequencies were continuously monitored and stored at 10 minute intervals. Animals were exposed to the following photoperiods: 28 days of 12L:12D, 19 days of 24L:0D and 16 days of 12L:12D. Light intensities tested varied between 0.1 to 100 lux. Rats received food and water ad libitum, and temperature and humidity were controlled throughout the study. The general health status of all rats was acceptable for each day of this study. No incidents of aggressive behavior were observed. Growth, locomotor activity, food and water consumption were comparable for all groups of animals, i.e, the circadian characteristics of the animals under these conditions were comparable. These results indicate that LED arrays are as effective in maintaining circadian rhythm stability as the commonly used cool-white fluorescent light sources. LEDs with their flexible spectrum, low energy requirements and minimal heat production have advantages for some chronopharmacology studies and

  9. High-Efficiency Nitride-Based Solid-State Lighting

    Energy Technology Data Exchange (ETDEWEB)

    Paul T. Fini; Shuji Nakamura

    2005-07-30

    In this final technical progress report we summarize research accomplished during Department of Energy contract DE-FC26-01NT41203, entitled ''High-Efficiency Nitride-Based Solid-State Lighting''. Two teams, from the University of California at Santa Barbara (Principle Investigator: Dr. Shuji Nakamura) and the Lighting Research Center at Rensselaer Polytechnic Institute (led by Dr. N. Narendran), pursued the goals of this contract from thin film growth, characterization, and packaging/luminaire design standpoints. The UCSB team initially pursued the development of blue gallium nitride (GaN)-based vertical-cavity surface-emitting lasers, as well as ultraviolet GaN-based light emitting diodes (LEDs). In Year 2, the emphasis shifted to resonant-cavity light emitting diodes, also known as micro-cavity LEDs when extremely thin device cavities are fabricated. These devices have very directional emission and higher light extraction efficiency than conventional LEDs. Via the optimization of thin-film growth and refinement of device processing, we decreased the total cavity thickness to less than 1 {micro}m, such that micro-cavity effects were clearly observed and a light extraction efficiency of over 10% was reached. We also began the development of photonic crystals for increased light extraction, in particular for so-called ''guided modes'' which would otherwise propagate laterally in the device and be re-absorbed. Finally, we pursued the growth of smooth, high-quality nonpolar a-plane and m-plane GaN films, as well as blue light emitting diodes on these novel films. Initial nonpolar LEDs showed the expected behavior of negligible peak wavelength shift with increasing drive current. M-plane LEDs in particular show promise, as unpackaged devices had unsaturated optical output power of {approx} 3 mW at 200 mA drive current. The LRC's tasks were aimed at developing the subcomponents necessary for packaging UCSB's light

  10. NANOSTRUCTURED HIGH PERFORMANCE ULTRAVIOLET AND BLUE LIGHT EMITTING DIODES FOR SOLID STATE LIGHTING

    Energy Technology Data Exchange (ETDEWEB)

    Arto V. Nurmikko; Jung Han

    2004-10-01

    We report on research results in this project which synergize advanced material science approaches with fundamental optical physics concepts pertaining to light-matter interaction, with the goal of solving seminal problems for the development of very high performance light emitting diodes (LEDs) in the blue and near ultraviolet for Solid State Lighting applications. Accomplishments in the first 12 month contract period include (1) new means of synthesizing zero- and one-dimensional GaN nanostructures, (2) establishment of the building blocks for making GaN-based microcavity devices, and (3) demonstration of top-down approach to nano-scale photonic devices for enhanced spontaneous emission and light extraction. These include a demonstration of eight-fold enhancement of the external emission efficiency in new InGaN QW photonic crystal structures. The body of results is presented in this report shows how a solid foundation has been laid, with several noticeable accomplishments, for innovative research, consistent with the stated milestones.

  11. High Temperature Chemical Kinetic Combustion Modeling of Lightly Methylated Alkanes

    Energy Technology Data Exchange (ETDEWEB)

    Sarathy, S M; Westbrook, C K; Pitz, W J; Mehl, M

    2011-03-01

    Conventional petroleum jet and diesel fuels, as well as alternative Fischer-Tropsch (FT) fuels and hydrotreated renewable jet (HRJ) fuels, contain high molecular weight lightly branched alkanes (i.e., methylalkanes) and straight chain alkanes (n-alkanes). Improving the combustion of these fuels in practical applications requires a fundamental understanding of large hydrocarbon combustion chemistry. This research project presents a detailed high temperature chemical kinetic mechanism for n-octane and three lightly branched isomers octane (i.e., 2-methylheptane, 3-methylheptane, and 2,5-dimethylhexane). The model is validated against experimental data from a variety of fundamental combustion devices. This new model is used to show how the location and number of methyl branches affects fuel reactivity including laminar flame speed and species formation.

  12. High-speed OCT light sources and systems [Invited

    OpenAIRE

    Klein, Thomas; Huber, Robert

    2017-01-01

    Imaging speed is one of the most important parameters that define the performance of optical coherence tomography (OCT) systems. During the last two decades, OCT speed has increased by over three orders of magnitude. New developments in wavelength-swept lasers have repeatedly been crucial for this development. In this review, we discuss the historical evolution and current state of the art of high-speed OCT systems, with focus on wavelength swept light sources and swept source OCT systems.

  13. High-speed OCT light sources and systems [Invited].

    Science.gov (United States)

    Klein, Thomas; Huber, Robert

    2017-02-01

    Imaging speed is one of the most important parameters that define the performance of optical coherence tomography (OCT) systems. During the last two decades, OCT speed has increased by over three orders of magnitude. New developments in wavelength-swept lasers have repeatedly been crucial for this development. In this review, we discuss the historical evolution and current state of the art of high-speed OCT systems, with focus on wavelength swept light sources and swept source OCT systems.

  14. High-speed OCT light sources and systems [Invited

    Science.gov (United States)

    Klein, Thomas; Huber, Robert

    2017-01-01

    Imaging speed is one of the most important parameters that define the performance of optical coherence tomography (OCT) systems. During the last two decades, OCT speed has increased by over three orders of magnitude. New developments in wavelength-swept lasers have repeatedly been crucial for this development. In this review, we discuss the historical evolution and current state of the art of high-speed OCT systems, with focus on wavelength swept light sources and swept source OCT systems. PMID:28270988

  15. HIGH-EFFICIENCY NITRIDE-BASED SOLID-STATE LIGHTING

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Paul T. Fini; Prof. Shuji Nakamura

    2002-04-30

    In this semiannual report we summarize the progress obtained in the first six months with the support of DoE contract No.DE-FC26-01NT41203, entitled ''High-Efficiency Nitride-Based Solid-State Lighting''. The two teams, from the University of California at Santa Barbara (Principle Investigator: Dr. Shuji Nakamura) and Rensselaer Polytechnic Institute (led by Dr. N. Narendran), are pursuing the goals of this contract from thin film growth, characterization, and packaging standpoints. The UCSB team has made significant progress in the development of GaN vertical cavity surface-emitting lasers (VCSELs) as well as light-emitting diodes (LEDs) with AlGaN active regions emitting in the ultraviolet (UV). The Rensselaer team has developed target specifications for some of the key parameters for the proposed solid-state lighting system, including a luminous flux requirement matrix for various lighting applications, optimal spectral power distributions, and the performance characteristics of currently available commercial LEDs for eventual comparisons to the devices developed in the scope of this project.

  16. HIGH-EFFICIENCY NITRIDE-BASED SOLID-STATE LIGHTING

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Paul T. Fini; Prof. Shuji Nakamura

    2002-09-01

    In this annual report we summarize the progress obtained in the first year with the support of DoE contract No.DE-FC26-01NT41203, entitled ''High-Efficiency Nitride-Based Solid-State Lighting''. The two teams, from the University of California at Santa Barbara (Principle Investigator: Dr. Shuji Nakamura) and Rensselaer Polytechnic Institute (led by Dr. N. Narendran), are pursuing the goals of this contract from thin film growth, characterization, and packaging standpoints. The UCSB team has made significant progress in the development of GaN vertical cavity surface-emitting lasers (VCSELs) as well as light-emitting diodes (LEDs) with AlGaN active regions emitting in the ultraviolet (UV). The Rensselaer team has developed target specifications for some of the key parameters for the proposed solid-state lighting system, including a luminous flux requirement matrix for various lighting applications, optimal spectral power distributions, and the performance characteristics of currently available commercial LEDs for eventual comparisons to the devices developed in the scope of this project.

  17. Development of high-performance solar LED lighting system

    KAUST Repository

    Huang, B.J.

    2010-08-01

    The present study developed a high-performance charge/discharge controller for stand-alone solar LED lighting system by incorporating an nMPPO system design, a PWM battery charge control, and a PWM battery discharge control to directly drive the LED. The MPPT controller can then be removed from the stand-alone solar system and the charged capacity of the battery increases 9.7%. For LED driven by PWM current directly from battery, a reliability test for the light decay of LED lamps was performed continuously for 13,200 h. It has shown that the light decay of PWM-driven LED is the same as that of constant-current driven LED. The switching energy loss of the MOSFET in the PWM battery discharge control is less than 1%. Three solar-powered LED lighting systems (18 W, 100 W and 150 W LED) were designed and built. The long-term outdoor field test results have shown that the system performance is satisfactory with the control system developed in the present study. The loss of load probability for the 18 W solar LED system is 14.1% in winter and zero in summer. For the 100 W solar LED system, the loss of load probability is 3.6% in spring. © 2009 Elsevier Ltd. All rights reserved.

  18. Lighting

    Data.gov (United States)

    Federal Laboratory Consortium — Lighting Systems Test Facilities aid research that improves the energy efficiency of lighting systems. • Gonio-Photometer: Measures illuminance from each portion of...

  19. High-Efficiency Nitride-Base Photonic Crystal Light Sources

    Energy Technology Data Exchange (ETDEWEB)

    James Speck; Evelyn Hu; Claude Weisbuch; Yong-Seok Choi; Kelly McGroddy; Gregor Koblmuller; Elison Matioli; Elizabeth Rangel; Fabian Rol; Dobri Simeonov

    2010-01-31

    The research activities performed in the framework of this project represent a major breakthrough in the demonstration of Photonic Crystals (PhC) as a competitive technology for LEDs with high light extraction efficiency. The goals of the project were to explore the viable approaches to manufacturability of PhC LEDS through proven standard industrial processes, establish the limits of light extraction by various concepts of PhC LEDs, and determine the possible advantages of PhC LEDs over current and forthcoming LED extraction concepts. We have developed three very different geometries for PhC light extraction in LEDs. In addition, we have demonstrated reliable methods for their in-depth analysis allowing the extraction of important parameters such as light extraction efficiency, modal extraction length, directionality, internal and external quantum efficiency. The information gained allows better understanding of the physical processes and the effect of the design parameters on the light directionality and extraction efficiency. As a result, we produced LEDs with controllable emission directionality and a state of the art extraction efficiency that goes up to 94%. Those devices are based on embedded air-gap PhC - a novel technology concept developed in the framework of this project. They rely on a simple and planar fabrication process that is very interesting for industrial implementation due to its robustness and scalability. In fact, besides the additional patterning and regrowth steps, the process is identical as that for standard industrially used p-side-up LEDs. The final devices exhibit the same good electrical characteristics and high process yield as a series of test standard LEDs obtained in comparable conditions. Finally, the technology of embedded air-gap patterns (PhC) has significant potential in other related fields such as: increasing the optical mode interaction with the active region in semiconductor lasers; increasing the coupling of the incident

  20. Nanostructured High Performance Ultraviolet and Blue Light Emitting Diodes for Solid State Lighting

    Energy Technology Data Exchange (ETDEWEB)

    Arto V. Nurmikko; Jung Han

    2007-03-31

    We report on research results in this project which synergize advanced material science approaches with fundamental optical physics concepts pertaining to light-matter interaction, with the goal of solving seminal problems for the development of very high performance light emitting diodes (LEDs) in the blue and near ultraviolet for Solid State Lighting applications. Accomplishments in the duration of the contract period include (i) new means of synthesizing AlGaN and InN quantum dots by droplet heteroepitaxy, (ii) synthesis of AlGaInN nanowires as building blocks for GaN-based microcavity devices, (iii) progress towards direct epitaxial alignment of the dense arrays of nanowires, (iv) observation and measurements of stimulated emission in dense InGaN nanopost arrays, (v) design and fabrication of InGaN photonic crystal emitters, and (vi) observation and measurements of enhanced fluorescence from coupled quantum dot and plasmonic nanostructures. The body of results is presented in this report shows how a solid foundation has been laid, with several noticeable accomplishments, for innovative research, consistent with the stated milestones.

  1. Nanostructured High Performance Ultraviolet and Blue Light Emitting Diodes for Solid State Lighting

    Energy Technology Data Exchange (ETDEWEB)

    Arto V. Nurmikko; Jung Han

    2005-09-30

    We report on research results in this project which synergize advanced material science approaches with fundamental optical physics concepts pertaining to light-matter interaction, with the goal of solving seminal problems for the development of very high performance light emitting diodes (LEDs) in the blue and near ultraviolet for Solid State Lighting applications. Accomplishments in the second 12 month contract period include (i) new means of synthesizing AlGaN and InN quantum dots by droplet heteroepitaxy, (ii) synthesis of AlGaInN nanowires as building blocks for GaN-based microcavity devices, (iii) progress towards direct epitaxial alignment of the dense arrays of nanowires, (iv) observation and measurements of stimulated emission in dense InGaN nanopost arrays, (v) design and fabrication of InGaN photonic crystal emitters, and (vi) observation and measurements of enhanced fluorescence from coupled quantum dot and plasmonic nanostructures. The body of results is presented in this report shows how a solid foundation has been laid, with several noticeable accomplishments, for innovative research, consistent with the stated milestones.

  2. High fluence light emitting diode-generated red light modulates characteristics associated with skin fibrosis.

    Science.gov (United States)

    Mamalis, Andrew; Koo, Eugene; Garcha, Manveer; Murphy, William J; Isseroff, R Rivkah; Jagdeo, Jared

    2016-12-01

    Skin fibrosis, often referred to as skin scarring, is a significant international health problem with limited treatment options. The hallmarks of skin fibrosis are increased fibroblast proliferation, collagen production, and migration speed. Recently published clinical observations indicate that visible red light may improve skin fibrosis. In this study we hypothesize that high-fluence light-emitting diode-generated red light (HF-LED-RL) modulates the key cellular features of skin fibrosis by decreasing cellular proliferation, collagen production, and migration speed of human skin fibroblasts. Herein, we demonstrate that HF-LED-RL increases reactive oxygen species (ROS) generation for up to 4 hours, inhibits fibroblast proliferation without increasing apoptosis, inhibits collagen production, and inhibits migration speed through modulation of the phosphoinositide 3-kinase (PI3K)/Akt pathway. We demonstrate that HF-LED-RL is capable of inhibiting the unifying cellular processes involved in skin fibrosis including fibroblast proliferation, collagen production, and migration speed. These findings suggest that HF-LED-RL may represent a new approach to treat skin fibrosis. LED advantages include low cost, portability, and ease of use. Further characterizing the photobiomodulatory effects of HF-LED-RL on fibroblasts and investigating the anti-fibrotic effects of HF-LED-RL in human subjects may provide new insight into the utility of this therapeutic approach for skin fibrosis. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. A squeezed light source operated under high vacuum.

    Science.gov (United States)

    Wade, Andrew R; Mansell, Georgia L; Chua, Sheon S Y; Ward, Robert L; Slagmolen, Bram J J; Shaddock, Daniel A; McClelland, David E

    2015-12-14

    Non-classical squeezed states of light are becoming increasingly important to a range of metrology and other quantum optics applications in cryptography, quantum computation and biophysics. Applications such as improving the sensitivity of advanced gravitational wave detectors and the development of space-based metrology and quantum networks will require robust deployable vacuum-compatible sources. To date non-linear photonics devices operated under high vacuum have been simple single pass systems, testing harmonic generation and the production of classically correlated photon pairs for space-based applications. Here we demonstrate the production under high-vacuum conditions of non-classical squeezed light with an observed 8.6 dB of quantum noise reduction down to 10 Hz. Demonstration of a resonant non-linear optical device, for the generation of squeezed light under vacuum, paves the way to fully exploit the advantages of in-vacuum operations, adapting this technology for deployment into new extreme environments.

  4. Assessment of the high performance light water reactor concept

    Energy Technology Data Exchange (ETDEWEB)

    Starflinger, J. [Univ. of Stuttgart, IKE, (Germany); Schulenberg, T. [Karlsruhe Inst. of Tech., Karlsruhe (Germany); Bittermann, D. [AREVA NP GmbH, Erlangen (Germany); Andreani, M. [Paul Scherrer Inst., Villigen (Switzerland); Maraczy, C. [AEKI-KFKI, Budapest (Hungary)

    2011-07-01

    From 2006-2010, the High Performance Light Water Reactor (HPLWR) was investigated within a European Funded project called HPLWR Phase 2. Operated at 25MPa with a heat-up rate in the core from 280{sup o}C to 500{sup o}C, this reactor concept provides a technological challenge in the fields of design, neutronics, thermal-hydraulics and heat transfer, materials, and safety. The assessment of the concept with respect to the goals of the technology roadmap for Generation IV Nuclear Reactors of the Generation IV International Forum shows that the HPLWR has a potential to fulfil the goals of economics, safety and proliferation resistance and physical protection. In terms of sustainability, the HPLWR with a thermal neutron spectrum investigated within this project, does not differ from existing Light Water Reactors in terms of usage of fuel and waste production. (author)

  5. Architecture of a highly modular lighting simulation system

    CERN Multimedia

    CERN. Geneva

    2014-01-01

    This talk will discuss the challenges before designing a highly modular, parallel, heterogeneous rendering system and their solutions. It will review how different lighting simulation algorithms could be combined to work together using an unified framework. We will discuss how the system can be instrumented for collecting data about the algorithms' runtime performance. The talk includes an overview of how collected data could be visualised in the computational domain of the lighting algorithms and be used for visual debugging and analysis. About the speaker Hristo Lesev has been working in the software industry for the last ten years. He has taken part in delivering a number of desktop and mobile applications. Computer Graphics programming is Hristo's main passion and he has experience writing extensions for 3D software like 3DS Max, Maya, Blender, Sketchup, and V-Ray. Since 2006 Hristo teaches Photorealistic Ray Tracing in the Faculty of Mathematics and Informatics at the Paisii Hilendarski...

  6. New robust and highly customizable light source management system

    Science.gov (United States)

    Minegishi, Yuji; Takahisa, Kenji; Ochiai, Hideyuki; Ohta, Takeshi; Enami, Tatsuo

    2015-03-01

    In semiconductor lithography, light sources play a significant role in the wafer production process as well as impacting the manufacturing cost per wafer. Chip manufacturers going forward will be challenged to develop new ways to become more cost effective than their competitors, and the software tools necessary to compete in this environment must be capable of effectively adapting to the unique needs of each manufacturer. Gigaphoton has developed a new highly customizable software system for managing light sources. It not only offers a simple and intuitive user interface that can be operated using a standard web browser on PCs, tablets, and smartphones, but also a platform for users and third parties to develop unique extensions and optimizations.

  7. High speed switching between arbitrary spatial light profiles.

    Science.gov (United States)

    Radwell, N; Brickus, D; Clark, T W; Franke-Arnold, S

    2014-06-02

    Complex images, inscribed into the spatial profile of a laser beam or even a single photon, offer a highly efficient method of data encoding. Here we present a prototype system which can quickly modulate between arbitrary images. We display an array of holograms, each defined by its phase and intensity profile, on a spatial light modulator. The input beam is then steered by an acousto-optic modulator to one of these holograms, where it is converted into the desired light mode. We demonstrate switching between characters within three separate alphabets at a switching rate of up to10 kHz. This rate is limited by our detection system, and we anticipate that the system is capable of far higher rates. Furthermore our system is not limited in efficiency by channel number, making it ideal for quantum communication applications.

  8. Light

    DEFF Research Database (Denmark)

    Prescott, N.B.; Kristensen, Helle Halkjær; Wathes, C.M.

    2004-01-01

    This chapter presents the effect of artificial light environments (light levels, colour, photoperiod and flicker) on the welfare of broilers in terms of vision, behaviour, lameness and mortality......This chapter presents the effect of artificial light environments (light levels, colour, photoperiod and flicker) on the welfare of broilers in terms of vision, behaviour, lameness and mortality...

  9. High mobility solution-processed hybrid light emitting transistors

    Science.gov (United States)

    Walker, Bright; Ullah, Mujeeb; Chae, Gil Jo; Burn, Paul L.; Cho, Shinuk; Kim, Jin Young; Namdas, Ebinazar B.; Seo, Jung Hwa

    2014-11-01

    We report the design, fabrication, and characterization of high-performance, solution-processed hybrid (inorganic-organic) light emitting transistors (HLETs). The devices employ a high-mobility, solution-processed cadmium sulfide layer as the switching and transport layer, with a conjugated polymer Super Yellow as an emissive material in non-planar source/drain transistor geometry. We demonstrate HLETs with electron mobilities of up to 19.5 cm2/V s, current on/off ratios of >107, and external quantum efficiency of 10-2% at 2100 cd/m2. These combined optical and electrical performance exceed those reported to date for HLETs. Furthermore, we provide full analysis of charge injection, charge transport, and recombination mechanism of the HLETs. The high brightness coupled with a high on/off ratio and low-cost solution processing makes this type of hybrid device attractive from a manufacturing perspective.

  10. Thin Film Packaging Solutions for High Efficiency OLED Lighting Products

    Energy Technology Data Exchange (ETDEWEB)

    None

    2008-06-30

    The objective of the 'Thin Film Packaging Solutions for High Efficiency OLED Lighting Products' project is to demonstrate thin film packaging solutions based on SiC hermetic coatings that, when applied to glass and plastic substrates, support OLED lighting devices by providing longer life with greater efficiency at lower cost than is currently available. Phase I Objective: Demonstrate thin film encapsulated working phosphorescent OLED devices on optical glass with lifetime of 1,000 hour life, CRI greater than 75, and 15 lm/W. Phase II Objective: Demonstrate thin film encapsulated working phosphorescent OLED devices on plastic or glass composite with 25 lm/W, 5,000 hours life, and CRI greater than 80. Phase III Objective: Demonstrate 2 x 2 ft{sup 2} thin film encapsulated working phosphorescent OLED with 40 lm/W, 10,000 hour life, and CRI greater than 85. This report details the efforts of Phase III (Budget Period Three), a fourteen month collaborative effort that focused on optimization of high-efficiency phosphorescent OLED devices and thin-film encapsulation of said devices. The report further details the conclusions and recommendations of the project team that have foundation in all three budget periods for the program. During the conduct of the Thin Film Packaging Solutions for High Efficiency OLED Lighting Products program, including budget period three, the project team completed and delivered the following achievements: (1) a three-year marketing effort that characterized the near-term and longer-term OLED market, identified customer and consumer lighting needs, and suggested prototype product concepts and niche OLED applications lighting that will give rise to broader market acceptance as a source for wide area illumination and energy conservation; (2) a thin film encapsulation technology with a lifetime of nearly 15,000 hours, tested by calcium coupons, while stored at 16 C and 40% relative humidity ('RH'). This encapsulation technology

  11. Light Initiated High Explosives (LIHE) Test Technique and Capabilities

    Science.gov (United States)

    Covert, Timothy

    2009-06-01

    The Light Initiated High Explosives (LIHE) test facility has been re-established and chartered to impart impulsive loads to a variety of targets. This loading is achieved through the detonation of a primary explosive applied directly to the target surface using a robotic spraying system. Using light as the initiating mechanism ensures virtually simultaneous loading. Uniform, discontinuous, or graded explosive loading conditions are achievable over complex shapes with the LIHE process. This direct detonation technique is a demonstrated capability at the LIHE facility. Test results will be presented. In addition to the direct detonation technique, the LIHE facility is developing the capability to explosively accelerate a thin flyer plate to impact various test targets. This explosively accelerated flyer plate (X-Flyer) will enable pressure control during impulsive loading. By controlling flyer density (material), thickness, velocity, and acceleration gap, the impact pressure amplitude and pulse duration can be controlled. Similar to the direct detonation technique, a primary explosive is robotically sprayed onto the flyer plate and subsequently detonated using an intense flash of light. Through the control of the explosive deposition and flyer gap, virtually simultaneous impact is achievable for either uniform or graded loading conditions. X-Flyer test results will be presented.

  12. High resolution X-ray spectroscopy in light antiprotonic atoms

    CERN Document Server

    Borchert, G L; Augsburger, M A; Castelli, C M; Chatellard, D; Egger, J P; El-Khoury, P; Elble, M; Gorke, H; Gotta, D; Hauser, P R; Indelicato, P J; Kirch, K; Lenz, S; Nelms, N; Rashid, K; Schult, O W B; Siems, T; Simons, L M

    2000-01-01

    At the LEAR facility, CERN, antiprotonic L alpha transitions in light elements have been investigated with a focussing crystal spectrometer. The high resolution of the experiment allowed for the first time to resolve in pH/pH the 2/sup 3/P/sub 0/ state from the close-lying states 2/sup 3/P/sub 2/, 2/sup 1/P/sub 1/, and 2/sup 3/P /sub 1/. In pD the corresponding transitions were found to be more than an order of magnitude broader. To a large extent the results for pH support the meson exchange model. (15 refs).

  13. High-performance lighting evaluated by photobiological parameters.

    Science.gov (United States)

    Rebec, Katja Malovrh; Gunde, Marta Klanjšek

    2014-08-10

    The human reception of light includes image-forming and non-image-forming effects which are triggered by spectral distribution and intensity of light. Ideal lighting is similar to daylight, which could be evaluated by spectral or chromaticity match. LED-based and CFL-based lighting were analyzed here, proposed according to spectral and chromaticity match, respectively. The photobiological effects were expressed by effectiveness for blue light hazard, cirtopic activity, and photopic vision. Good spectral match provides light with more similar effects to those obtained by the chromaticity match. The new parameters are useful for better evaluation of complex human responses caused by lighting.

  14. High-Voltage LED Light Engine with Integrated Driver

    Energy Technology Data Exchange (ETDEWEB)

    Soer, Wouter [Lumileds LLC, San Jose, CA (United States)

    2016-02-29

    LED luminaires have seen dramatic changes in cost breakdown over the past few years. The LED component cost, which until recently was the dominant portion of luminaire cost, has fallen to a level of the same order as the other luminaire components, such as the driver, housing, optics etc. With the current state of the technology, further luminaire performance improvement and cost reduction is realized most effectively by optimization of the whole system, rather than a single component. This project focuses on improving the integration between LEDs and drivers. Lumileds has developed a light engine platform based on low-cost high-power LEDs and driver topologies optimized for integration with these LEDs on a single substrate. The integration of driver and LEDs enables an estimated luminaire cost reduction of about 25% for targeted applications, mostly due to significant reductions in driver and housing cost. The high-power LEDs are based on Lumileds’ patterned sapphire substrate flip-chip (PSS-FC) technology, affording reduced die fabrication and packaging cost compared to existing technology. Two general versions of PSS-FC die were developed in order to create the desired voltage and flux increments for driver integration: (i) small single-junction die (0.5 mm2), optimal for distributed lighting applications, and (ii) larger multi-junction die (2 mm2 and 4 mm2) for high-power directional applications. Two driver topologies were developed: a tapped linear driver topology and a single-stage switch-mode topology, taking advantage of the flexible voltage configurations of the new PSS-FC die and the simplification opportunities enabled by integration of LEDs and driver on the same board. A prototype light engine was developed for an outdoor “core module” application based on the multi-junction PSS-FC die and the single-stage switch-mode driver. The light engine meets the project efficacy target of 128 lm/W at a luminous flux

  15. Design concept of the high performance light water reactor

    Energy Technology Data Exchange (ETDEWEB)

    Schulenberg, Thomas; Starflinger, Joerg [Forschungszentrum Karlsruhe GmbH Technik und Umwelt (Germany). Inst. for Nuclear and Energy Technologies; Bittermann, Dietmar [AREVA NP GmbH, Erlangen (Germany). NEP-G Process

    2009-04-15

    The 'High Performance Light Water Reactor' (HPLWR) is a Light Water Reactor operating with supercritical water as coolant. At a pressure of 25 MPa in the core, water is heated up from 280 to 500 C. For these conditions, the envisaged net plant efficiency is 43.5%. The core design concept is based on a so-called '3-pass-core' in which the coolant is heated up in three subsequent steps. After each step, the coolant is mixed avoiding hot streaks possibly leading to unacceptable wall temperatures. The design of such a core comprises fuel assemblies containing 40 fuel rods and an inner and outer box for a better neutron moderation. Nine of these are assembled to a cluster with common head- and foot piece. The coolant is mixed inside an upper and inside a lower mixing chamber and leaves the reactor pressure vessel through a co-axial pipe, which protects the vessel wall against too high temperatures. (orig.)

  16. New application of superconductors: High sensitivity cryogenic light detectors

    Energy Technology Data Exchange (ETDEWEB)

    Cardani, L., E-mail: laura.cardani@roma1.infn.it [Dipartimento di Fisica, Sapienza Università di Roma, Piazzale Aldo Moro 2, 00185 Roma (Italy); Physics Department, Princeton University, Washington Road, 08544 Princeton, NJ (United States); Bellini, F.; Casali, N. [Dipartimento di Fisica, Sapienza Università di Roma, Piazzale Aldo Moro 2, 00185 Roma (Italy); INFN – Sezione di Roma, Piazzale Aldo Moro 2, 00185 Roma, Italy (Italy); Castellano, M.G. [Istituto di Fotonica e Nanotecnologie – CNR, Via Cineto Romano 42, 00156 Roma (Italy); Colantoni, I.; Coppolecchia, A. [Dipartimento di Fisica, Sapienza Università di Roma, Piazzale Aldo Moro 2, 00185 Roma (Italy); Cosmelli, C.; Cruciani, A. [Dipartimento di Fisica, Sapienza Università di Roma, Piazzale Aldo Moro 2, 00185 Roma (Italy); INFN – Sezione di Roma, Piazzale Aldo Moro 2, 00185 Roma, Italy (Italy); D' Addabbo, A. [INFN – Laboratori Nazionali del Gran Sasso, Assergi (L' Aquila) 67010 (Italy); Di Domizio, S. [INFN – Sezione di Genova, Via Dodecaneso 33, 16146 Genova (Italy); Dipartimento di Fisica, Università degli Studi di Genova, Via Dodecaneso 33, 16146 Genova (Italy); Martinez, M. [Dipartimento di Fisica, Sapienza Università di Roma, Piazzale Aldo Moro 2, 00185 Roma (Italy); INFN – Sezione di Roma, Piazzale Aldo Moro 2, 00185 Roma, Italy (Italy); Laboratorio de Fisica Nuclear y Astroparticulas, Universidad de Zaragoza, Zaragoza 50009 (Spain); Tomei, C. [INFN – Sezione di Roma, Piazzale Aldo Moro 2, 00185 Roma, Italy (Italy); and others

    2017-02-11

    In this paper we describe the current status of the CALDER project, which is developing ultra-sensitive light detectors based on superconductors for cryogenic applications. When we apply an AC current to a superconductor, the Cooper pairs oscillate and acquire kinetic inductance, that can be measured by inserting the superconductor in a LC circuit with high merit factor. Interactions in the superconductor can break the Cooper pairs, causing sizable variations in the kinetic inductance and, thus, in the response of the LC circuit. The continuous monitoring of the amplitude and frequency modulation allows to reconstruct the incident energy with excellent sensitivity. This concept is at the basis of Kinetic Inductance Detectors (KIDs) that are characterized by natural aptitude to multiplexed read-out (several sensors can be tuned to different resonant frequencies and coupled to the same line), resolution of few eV, stable behavior over a wide temperature range, and ease in fabrication. We present the results obtained by the CALDER collaboration with 2×2 cm{sup 2} substrates sampled by 1 or 4 Aluminum KIDs. We show that the performances of the first prototypes are already competitive with those of other commonly used light detectors, and we discuss the strategies for a further improvement.

  17. Highly efficient light-emitting diodes based on intramolecular rotation

    CERN Document Server

    Di, Dawei; Yang, Le; Jones, Saul; Friend, Richard H; Linnolahti, Mikko; Bochmann, Manfred; Credgington, Dan

    2016-01-01

    The efficiency of an organic light-emitting diode (OLED) is fundamentally governed by the spin of recombining electron-hole pairs (singlet and triplet excitons), since triplets cannot usually emit light. The singlet-triplet energy gap, a key factor for efficient utilization of triplets, is normally positive. Here we show that in a family of materials with amide donor and carbene acceptor moieties linked by a metal, this energy gap for singlet and triplet excitons with charge-transfer character can be tuned from positive to negative values via the rotation of donor and acceptor about the metal-amide bond. When the gap is close to zero, facile intersystem crossing is possible, enabling efficient emission from singlet excitons. We demonstrate solution-processed LEDs with exceptionally high quantum efficiencies (near-100% internal and >27% external quantum efficiencies), and current and power efficiencies (87 cd/A and 75 lm/W) comparable to, or exceeding, those of state-of-the-art vacuum-processed OLEDs and quant...

  18. Combinational light emitting diode-high frequency focused ultrasound treatment for HeLa cell.

    Science.gov (United States)

    Choe, Se-Woon; Park, Kitae; Park, Chulwoo; Ryu, Jaemyung; Choi, Hojong

    2017-12-01

    Light sources such as laser and light emitting diode or ultrasound devices have been widely used for cancer therapy and regenerative medicines, since they are more cost-effective and less harmful than radiation therapy, chemotherapy or magnetic treatment. Compared to laser and low intensity ultrasound techniques, light emitting diode and high frequency focused ultrasound shows enhanced therapeutic effects, especially for small tumors. We propose combinational light emitting diode-high frequency focused ultrasound treatment for human cervical cancer HeLa cells. Individual red, green, and blue light emitting diode light only, high frequency focused ultrasound only, or light emitting diode light combined with high frequency focused ultrasound treatments were applied in order to characterize the responses of HeLa cells. Cell density exposed by blue light emitting diode light combined with high frequency focused ultrasound (2.19 ± 0.58%) was much lower than that of cells exposed by red and green light emitting diode lights (81.71 ± 9.92% and 61.81 ± 4.09%), blue light emitting diode light (11.19 ± 2.51%) or high frequency focused ultrasound only (9.72 ± 1.04%). We believe that the proposed combinational blue light emitting diode-high frequency focused ultrasound treatment could have therapeutic benefits to alleviate cancer cell proliferation.

  19. High-performance next-generation EUV lithography light source

    Science.gov (United States)

    Choi, Peter; Zakharov, Sergey V.; Aliaga-Rossel, Raul; Benali, Otman; Duffy, Grainne; Sarroukh, Ouassima; Wyndham, Edmund; Zakharov, Vasily S.

    2009-03-01

    EUVL solution for HVM at the 22 nm node requires a high power long-term EUV source operation with hundreds of watts at the intermediate focus output. EUV mask blank and mask defects inspections require at-wavelength tools with high brightness. Theoretical analysis with a 2-D radiation MHD code Z* has been performed to address key issues in EUV plasma sources with radiation transfer. The study shows that self-absorption defines the limiting brightness of a single EUV source, which cannot meet the requirements of the HVM tool with high efficiency and is not sufficient for critical metrology applications, given the limiting etendue of the optics. It is shown that the required irradiance can be achieved by spatial multiplexing, using multiple small sources. We present here details of the study, as well as experimental results from a novel EUV light source with an intrinsic photon collector demonstrating high brightness, the i-SoCoMo concept, where an impulse micro discharge plasma source is integrated to a photon collector based on an active plasma structure. The small physical size and low etendue properties of the i-SoCoMo unit allows a large number of such sources to be put together in one physical package and be operated in a multiplexed fashion to meet necessary power requirements.

  20. Mobile learning and high-lighting language education

    DEFF Research Database (Denmark)

    Vinther, Jane

    advantage of the social side in their application. The aim has been to make language classes attractive and relevant and to highlight the attractiveness and fun in learning through web 2.0 and mobile units. The overall project was supported by the Danish ministry of education as well as the individual......-line and individually to assess the effect of the projects on student motivation and autonomy. The investigation throws light on personal experiences as well as the generally perceived image and status of foreign language learning in upper secondary school. The results of the study are not fully analysed at the present......Mobile learning and high-profiling language education. The number of students learning a second or foreign language and participating in instruction in languages other than English has been in decline for some time. There seems to be such a general tendency across nations albeit for a variety...

  1. Handling high data rate detectors at Diamond Light Source

    Science.gov (United States)

    Pedersen, U. K.; Rees, N.; Basham, M.; Ferner, F. J. K.

    2013-03-01

    An increasing number of area detectors, in use at Diamond Light Source, produce high rates of data. In order to capture, store and process this data High Performance Computing (HPC) systems have been implemented. This paper will present the architecture and usage for handling high rate data: detector data capture, large volume storage and parallel processing. The EPICS area Detector frame work has been adopted to abstract the detectors for common tasks including live processing, file format and storage. The chosen data format is HDF5 which provides multidimensional data storage and NeXuS compatibility. The storage system and related computing infrastructure include: a centralised Lustre based parallel file system, a dedicated network and a HPC cluster. A well defined roadmap is in place for the evolution of this to meet demand as the requirements and technology advances. For processing the science data the HPC cluster allow efficient parallel computing, on a mixture of ×86 and GPU processing units. The nature of the Lustre storage system in combination with the parallel HDF5 library allow efficient disk I/O during computation jobs. Software developments, which include utilising optimised parallel file reading for a variety of post processing techniques, are being developed in collaboration as part of the Pan-Data EU Project (www.pan-data.eu). These are particularly applicable to tomographic reconstruction and processing of non crystalline diffraction data.

  2. Integrated Automotive High-Power LED-Lighting Systems in 3D-MID Technology

    NARCIS (Netherlands)

    Thomas, W.

    2014-01-01

    The growing energy consumption of lighting as well as rising luminous efficacies and -fluxes of high-power Light Emitting Diodes (LEDs) have contributed to the widespread use of LEDs in modern lighting systems. One of the most prominent users of the LED-technology is automotive (exterior) lighting.

  3. Light

    CERN Document Server

    Robertson, William C

    2003-01-01

    Why is left right and right left in the mirror? Baffled by the basics of reflection and refraction? Wondering just how the eye works? If you have trouble teaching concepts about light that you don t fully grasp yourself, get help from a book that s both scientifically accurate and entertaining with Light. By combining clear explanations, clever drawings, and activities that use easy-to-find materials, this book covers what science teachers and parents need to know to teach about light with confidence. It uses ray, wave, and particle models of light to explain the basics of reflection and refraction, optical instruments, polarization of light, and interference and diffraction. There s also an entire chapter on how the eye works. Each chapter ends with a Summary and Applications section that reinforces concepts with everyday examples. Whether you need a deeper understanding of how light bends or a good explanation of why the sky is blue, you ll find Light more illuminating and accessible than a college textbook...

  4. High Energy Density Science at the Linac Coherent Light Source

    Energy Technology Data Exchange (ETDEWEB)

    Lee, R W

    2007-10-19

    High energy density science (HEDS), as a discipline that has developed in the United States from National Nuclear Security Agency (NNSA)-sponsored laboratory research programs, is, and will remain, a major component of the NNSA science and technology strategy. Its scientific borders are not restricted to NNSA. 'Frontiers in High Energy Density Physics: The X-Games of Contemporary Science' identified numerous exciting scientific opportunities in this field, while pointing to the need for a overarching interagency plan for its evolution. Meanwhile, construction of the first x-ray free-electron laser, the Office-of-Science-funded Linear Coherent Light Source-LCLS: the world's first free electron x-ray laser, with 100-fsec time resolution, tunable x-ray energies, a high rep rate, and a 10 order-of-magnitude increase in brightness over any other x-ray source--led to the realization that the scientific needs of NNSA and the broader scientific community could be well served by an LCLS HEDS endstation employing both short-pulse and high-energy optical lasers. Development of this concept has been well received in the community. NNSA requested a workshop on the applicability of LCLS to its needs. 'High Energy Density Science at the LCLS: NNSA Defense Programs Mission Need' was held in December 2006. The workshop provided strong support for the relevance of the endstation to NNSA strategic requirements. The range of science that was addressed covered a wide swath of the vast HEDS phase space. The unique possibilities provided by the LCLS in areas of intense interest to NNSA Defense Programs were discussed. The areas of focus included warm dense matter and equations of state, hot dense matter, and behavior of high-pressure materials under conditions of high strain-rate and extreme dynamic loading. Development of new and advanced diagnostic techniques was also addressed. This report lays out the relevant science, as brief summaries (Ch. II), expanded

  5. High light extraction efficiency in bulk-GaN based volumetric violet light-emitting diodes

    Science.gov (United States)

    David, Aurelien; Hurni, Christophe A.; Aldaz, Rafael I.; Cich, Michael J.; Ellis, Bryan; Huang, Kevin; Steranka, Frank M.; Krames, Michael R.

    2014-12-01

    We report on the light extraction efficiency of III-Nitride violet light-emitting diodes with a volumetric flip-chip architecture. We introduce an accurate optical model to account for light extraction. We fabricate a series of devices with varying optical configurations and fit their measured performance with our model. We show the importance of second-order optical effects like photon recycling and residual surface roughness to account for data. We conclude that our devices reach an extraction efficiency of 89%.

  6. Slow Light at High Frequencies in an Amplifying Semiconductor Waveguide

    DEFF Research Database (Denmark)

    Öhman, Filip; Yvind, Kresten; Mørk, Jesper

    2006-01-01

    We demonstrate slow-down of a modulated light signal in a semiconductor waveguide. Concatenated amplifying and absorbing sections simultaneously achieve both amplification and a controllable time delay at 15 GHz.......We demonstrate slow-down of a modulated light signal in a semiconductor waveguide. Concatenated amplifying and absorbing sections simultaneously achieve both amplification and a controllable time delay at 15 GHz....

  7. πSPIM: high NA high resolution isotropic light-sheet imaging in cell culture dishes.

    Science.gov (United States)

    Theer, Patrick; Dragneva, Denitsa; Knop, Michael

    2016-09-13

    Light-sheet fluorescence microscopy (LSFM), also termed single plane illumination microscopy (SPIM), enables live cell fluorescence imaging with optical sectioning capabilities superior to confocal microscopy and without any out-of-focus exposure of the specimen. However, the need of two objective lenses, one for light-sheet illumination and one for imaging, imposes geometrical constraints that require LSFM setups to be adapted to the specific needs of different types of specimen in order to obtain optimal imaging conditions. Here we demonstrate the use of an oblique light-sheet configuration adapted to provide the highest possible Gaussian beam enabled resolution in LSFM. The oblique light-sheet configuration furthermore enables LSFM imaging at the surface of a cover slip, without the need of specific sample mounting. In addition, the system is compatible with simultaneous high NA wide-field epi-fluorescence imaging of the specimen contained in a glass-bottom cell culture dish. This prevents cumbersome sample mounting and enables rapid screening of large areas of the specimen followed by high-resolution LSFM imaging of selected cells. We demonstrate the application of this microscope for in toto imaging of endocytosis in yeast, showing for the first time imaging of all endocytic events of a given cell over a period of >5 minutes with sub-second resolution.

  8. Light

    CERN Document Server

    Ditchburn, R W

    1963-01-01

    This classic study, available for the first time in paperback, clearly demonstrates how quantum theory is a natural development of wave theory, and how these two theories, once thought to be irreconcilable, together comprise a single valid theory of light. Aimed at students with an intermediate-level knowledge of physics, the book first offers a historical introduction to the subject, then covers topics such as wave theory, interference, diffraction, Huygens' Principle, Fermat's Principle, and the accuracy of optical measurements. Additional topics include the velocity of light, relativistic o

  9. Plant Control of the High Performance Light Water Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Schlagenhaufer, Marc; Starflinger, J.; Schulenberg, T. [Institute for Nuclear and Energy Technologies, Forschungszentrum Karlsruhe GmbH, Hermann-von-Helmholtz-Platz 1, Eggenstein-Leopoldshafen, Baden-Wuertemberg 76344 (Germany)

    2009-06-15

    The latest design concept of the High Performance Light Water Reactor (HPLWR) includes a thermal core in which supercritical water at 25 MPa inlet pressure is heated up from 280 deg. C reactor inlet temperature to 500 deg. C core exit temperature in three steps with intermediate coolant mixing to minimize peak cladding temperatures of the fuel rods. A direct supercritical steam cycle of the HPLWR has been designed with high, intermediate and low pressure turbines with a single reheat to 441 deg. C at 4.04 MPa pressure. Three low pressure pre-heaters and four high pressure pre-heaters are foreseen to achieve the envisaged reactor inlet temperature of 280 deg. C at full load. A feedwater tank of 603 m{sup 3} at 0.55 MPa pressure serves as an accumulator for normal and accidental conditions. The steam cycle has been modelled with APROS, developed by VTT Finland, to provide thermodynamic data and cycle efficiency values under full load and part load operation conditions as well as the transient response to load changes. A plant control system has been designed in which the reactor inlet pressure is controlled by the turbine valve, the reactor power is controlled by the feedwater pumps while the life steam temperature is controlled by control rods, and the reheat temperature is controlled by the reheater valve. Neglecting the reactivity control, the core power can also be treated as input parameter such that the life steam temperature is directly controlled by the feedwater mass flow. The plant control can handle all loading and de-loading cycles including complete shut down. A constant pressure at reactor inlet is foreseen for all load cases. Peak temperatures of the fuel pins are checked with a simplified core model. Two shut down procedures starting at 50% load are presented. A reactor scram with turbine states the safe shut down of the whole plant. To avoid hard material temperature changes, a controlled shut down procedure is designed. The rotational speed of the

  10. Productivity of Chlorella sorokiniana in a short light-path (SLP) panel photobioreactor under high irradiance

    NARCIS (Netherlands)

    Cuaresma, M.; Janssen, M.G.J.; Vilchez, C.; Wijffels, R.H.

    2009-01-01

    Maximal productivity of a 14 mm light-path panel photobioreactor under high irradiance was determined. Under continuous illumination of 2,100 µmol photons m-2 s-1 with red light emitting diodes (LEDs) the effect of dilution rate on photobioreactor productivity was studied. The light intensity used

  11. Negative Lens–Induced Myopia in Infant Monkeys: Effects of High Ambient Lighting

    Science.gov (United States)

    Smith, Earl L.; Hung, Li-Fang; Arumugam, Baskar; Huang, Juan

    2013-01-01

    Purpose. To determine whether high light levels, which have a protective effect against form-deprivation myopia, also retard the development of lens-induced myopia in primates. Methods. Hyperopic defocus was imposed on 27 monkeys by securing −3 diopter (D) lenses in front of one eye. The lens-rearing procedures were initiated at 24 days of age and continued for periods ranging from 50 to 123 days. Fifteen of the treated monkeys were exposed to normal laboratory light levels (∼350 lux). For the other 12 lens-reared monkeys, auxiliary lighting increased the illuminance to 25,000 lux for 6 hours during the middle of the daily 12 hour light cycle. Refractive development, corneal power, and axial dimensions were assessed by retinoscopy, keratometry, and ultrasonography, respectively. Data were also obtained from 37 control monkeys, four of which were exposed to high ambient lighting. Results. In normal- and high-light-reared monkeys, hyperopic defocus accelerated vitreous chamber elongation and produced myopic shifts in refractive error. The high light regimen did not alter the degree of myopia (high light: −1.69 ± 0.84 D versus normal light: −2.08 ± 1.12 D; P = 0.40) or the rate at which the treated eyes compensated for the imposed defocus. Following lens removal, the high light monkeys recovered from the induced myopia. The recovery process was not affected by the high lighting regimen. Conclusions. In contrast to the protective effects that high ambient lighting has against form-deprivation myopia, high artificial lighting did not alter the course of compensation to imposed defocus. These results indicate that the mechanisms responsible for form-deprivation myopia and lens-induced myopia are not identical. PMID:23557736

  12. Negative lens-induced myopia in infant monkeys: effects of high ambient lighting.

    Science.gov (United States)

    Smith, Earl L; Hung, Li-Fang; Arumugam, Baskar; Huang, Juan

    2013-04-26

    To determine whether high light levels, which have a protective effect against form-deprivation myopia, also retard the development of lens-induced myopia in primates. Hyperopic defocus was imposed on 27 monkeys by securing -3 diopter (D) lenses in front of one eye. The lens-rearing procedures were initiated at 24 days of age and continued for periods ranging from 50 to 123 days. Fifteen of the treated monkeys were exposed to normal laboratory light levels (∼350 lux). For the other 12 lens-reared monkeys, auxiliary lighting increased the illuminance to 25,000 lux for 6 hours during the middle of the daily 12 hour light cycle. Refractive development, corneal power, and axial dimensions were assessed by retinoscopy, keratometry, and ultrasonography, respectively. Data were also obtained from 37 control monkeys, four of which were exposed to high ambient lighting. in normal- and high-light-reared monkeys, hyperopic defocus accelerated vitreous chamber elongation and produced myopic shifts in refractive error. the high light regimen did not alter the degree of myopia (high light: -1.69 ± 0.84 D versus normal light: -2.08 ± 1.12 D; P = 0.40) or the rate at which the treated eyes compensated for the imposed defocus. Following lens removal, the high light monkeys recovered from the induced myopia. The recovery process was not affected by the high lighting regimen. In contrast to the protective effects that high ambient lighting has against form-deprivation myopia, high artificial lighting did not alter the course of compensation to imposed defocus. These results indicate that the mechanisms responsible for form-deprivation myopia and lens-induced myopia are not identical.

  13. A high-efficiency indirect lighting system utilizing the solar 1000 sulfur lamp

    Energy Technology Data Exchange (ETDEWEB)

    Siminovitch, M.; Gould, C.; Page, E.

    1997-06-01

    High-lumen light sources represent unique challenges and opportunities for the design of practical and efficient interior lighting systems. High-output sources require a means of large-scale distribution and avoidance of high-luminance glare while providing efficient delivery. An indirect lighting system has been developed for use with a 1,000 Watt sulfur lamp that efficiently utilizes the high-output source to provide quality interior lighting. This paper briefly describes the design and initial testing of this new system.

  14. High power AlGaN ultraviolet light emitters

    Science.gov (United States)

    Shatalov, Max; Sun, Wenhong; Jain, Rakesh; Lunev, Alex; Hu, Xuhong; Dobrinsky, Alex; Bilenko, Yuri; Yang, Jinwei; Garrett, Gregory A.; Rodak, Lee E.; Wraback, Michael; Shur, Michael; Gaska, Remis

    2014-06-01

    We present the analysis of the external quantum efficiency in AlGaN deep ultraviolet (DUV) light-emitting diodes (LEDs) on sapphire substrates and discuss factors affecting the output power of DUV LEDs. Performance of the LED is related to optimization of the device structure design and improvements of the epitaxial material quality.

  15. A high efficiency lateral light emitting device on SOI

    NARCIS (Netherlands)

    Hoang, T.; Le Minh, P.; Holleman, J.; Zieren, V.; Goossens, M.J.; Schmitz, Jurriaan

    2005-01-01

    The infrared light emission of lateral p/sup +/-p-n/sup +/ diodes realized on SIMOX-SOI (separation by implantation of oxygen - silicon on insulator) substrates has been studied. The confinement of the free carriers in one dimension due to the buried oxide was suggested to be a key point to increase

  16. High dynamic, spectral, and polarized natural light environment acquisition

    Science.gov (United States)

    Porral, Philippe; Callet, Patrick; Fuchs, Philippe; Muller, Thomas; Sandré-Chardonnal, Etienne

    2015-03-01

    In the field of image synthesis, the simulation of material's appearance requires a rigorous resolution of the light transport equation. This implies taking into account all the elements that may have an influence on the spectral radiance, and that are perceived by the human eye. Obviously, the reflectance properties of the materials have a major impact in the calculations, but other significant properties of light such as spectral distribution and polarization must also be taken into account, in order to expect correct results. Unfortunately real maps of the polarized or spectral environment corresponding to a real sky do not exist. Therefore, it seemed necessary to focus our work on capturing such data, in order to have a system that qualifies all the properties of light and capable of powering simulations in a renderer software. As a consequence, in this work, we develop and characterize a device designed to capture the entire light environment, by taking into account both the dynamic range of the spectral distribution and the polarization states, in a measurement time of less than two minutes. We propose a data format inspired by polarimetric imaging and fitted for a spectral rendering engine, which exploits the "Stokes-Mueller formalism."

  17. Stability analysis of the high performance light water reactor

    Energy Technology Data Exchange (ETDEWEB)

    Ortega Gomez, Tino

    2009-03-15

    In the Generation IV international advanced nuclear reactor development program, the High Performance Light Water Reactor (HPLWR) is one of the most promising candidates. Important features are its inherently high thermodynamic efficiency (of approximately 45 %) and the ability to use existing supercritical water technology which previously has been developed and deployed for fossil fired power plants. Within a HPLWR core, the fluid experiences a drastic change in thermal and transport properties such as density, dynamic viscosity, specific heat and thermal conductivity, as the supercritical water is heated from 280 C to 500 C. The density change substantially exceeds that in a Boiling Water Reactor (i.e., HPLWR: density changes from 780 kg/m{sup 3} to 90 kg/m{sup 3}; BWR: density changes from 750 kg/m{sup 3} to 198 kg/m3). Due to this density change, the HPLWR can be - under certain operation parameters - susceptible to various thermal-hydraulic flow instabilities, which have to be avoided. In this thesis a stability analysis for the HPLWR is presented. This analysis is based on analytical considerations and numerical results, which were obtained by a computer code developed by the author. The heat-up stages of the HPLWR three-pass core are identified in respect to the relevant flow instability phenomena. The modeling approach successfully used for BWR stability analysis is extended to supercritical pressure operation conditions. In particular, a one-dimensional equation set representing the coolant flow of HPLWR fuel assemblies has been implemented in a commercial software named COMSOL to perform steady-state, time-dependent, and modal analyses. An investigation of important static instabilities (i.e., Ledinegg instabilities, flow maldistribution) and Pressure Drop Oscillations (PDO) have been carried out and none were found under operation conditions of the HPLWR. Three types of Density Wave Oscillation (DWO) modes have been studied: the single channel DWO, the

  18. Defining the light emitting area for displays in the unipolar regime of highly efficient light emitting transistors

    Science.gov (United States)

    Ullah, Mujeeb; Armin, Ardalan; Tandy, Kristen; Yambem, Soniya D.; Burn, Paul L.; Meredith, Paul; Namdas, Ebinazar B.

    2015-01-01

    Light-emitting field effect transistors (LEFETs) are an emerging class of multifunctional optoelectronic devices. It combines the light emitting function of an OLED with the switching function of a transistor in a single device architecture. The dual functionality of LEFETs has the potential applications in active matrix displays. However, the key problem of existing LEFETs thus far has been their low EQEs at high brightness, poor ON/OFF and poorly defined light emitting area - a thin emissive zone at the edge of the electrodes. Here we report heterostructure LEFETs based on solution processed unipolar charge transport and an emissive polymer that have an EQE of up to 1% at a brightness of 1350 cd/m2, ON/OFF ratio > 104 and a well-defined light emitting zone suitable for display pixel design. We show that a non-planar hole-injecting electrode combined with a semi-transparent electron-injecting electrode enables to achieve high EQE at high brightness and high ON/OFF ratio. Furthermore, we demonstrate that heterostructure LEFETs have a better frequency response (fcut-off = 2.6 kHz) compared to single layer LEFETs. The results presented here therefore are a major step along the pathway towards the realization of LEFETs for display applications. PMID:25743444

  19. High light intensity mediates a shift from allochthonous to autochthonous carbon use in phototrophic stream biofilms

    Science.gov (United States)

    Wagner, Karoline; Bengtsson, Mia M.; Findlay, Robert H.; Battin, Tom J.; Ulseth, Amber J.

    2017-07-01

    Changes in the riparian vegetation along stream channels, diurnal light availability, and longitudinal fluctuations in the local light regime in streams influence primary production and carbon (C) cycling in benthic stream biofilms. To investigate the influence of light availability on the uptake dynamics of autochthonous and allochthonous dissolved organic carbon (DOC) in benthic biofilms, we experimentally added 13C-labeled allochthonous DOC to biofilms grown under light intensities ranging from 5 to 152 μmol photons m-2 s-1. We calculated the net C flux, which showed that benthic biofilms released autochthonous DOC across the entire light gradient. Light availability and diurnal light patterns influenced C uptake by benthic biofilms. More allochthonous DOC was respired under low light availability and at night, whereas under high light availability and during the day mainly autochthonous C was respired by the benthic biofilm community. Furthermore, phenol oxidase activity (indicative of allochthonous DOC uptake) was more elevated under low light availability, whereas beta-glucosidase activity (indicative of autochthonous DOC use) increased with light intensity. Collectively, our results suggest that biofilms exposed to high light inputs preferentially used autochthonous DOC, whereas biofilms incubated at attenuated levels showed greater use of allochthonous DOC. This has implications for the spatial dynamics of DOC uptake in streams and speaks against the occurrence of priming effects in algal-dominated stream biofilms.

  20. Designing large, high-efficiency, high-numerical-aperture, transmissive meta-lenses for visible light

    CERN Document Server

    Byrnes, Steven J; Aieta, Francesco; Capasso, Federico

    2015-01-01

    A metasurface lens (meta-lens) is a lens that bends light with an array of nanostructures on a flat surface, rather than by refraction. Macroscopic meta-lenses (mm- to cm-scale diameter) have been quite difficult to simulate and optimize, due to the large area, the lack of periodicity, and the billions of adjustable parameters. We describe a method for designing a large-area meta-lens that allows not only prediction of the efficiency and far-field, but also optimization of the shape and position of each individual nanostructure, with a computational cost that is almost independent of the lens size. Loosely speaking, the technique consists of designing a series of metasurface beam deflectors (blazed gratings), and then gluing them together. As a test of this framework, we design some high-numerical-aperture (NA=0.94) meta-lenses for visible light, based on TiO2 nano-pillars on a glass substrate. One of our designs is predicted to focus unpolarized 580nm light with 79% predicted efficiency; another focuses 580n...

  1. Water cooling of high power light emitting diode

    DEFF Research Database (Denmark)

    Sørensen, Henrik

    2012-01-01

    The development in light technologies for entertainment is moving towards LED based solutions. This progress is not without problems, when more than a single LED is used. The amount of generated heat is often in the same order as in a conventional discharge lamp, but the allowable operating tempe......; axial flow through mini channels or a s-channel. Experiments showed that the channel design utilizing swirling flows had up to 4 times the pressure loss as the mini channel/s-channel....

  2. High resolution 2D image upconversion of incoherent light

    DEFF Research Database (Denmark)

    Dam, Jeppe Seidelin; Pedersen, Christian; Tidemand-Lichtenberg, Peter

    2011-01-01

    An optimized method for continuous wave 2-dimensional (2-D) upconversion of incoherent or thermal light is demonstrated and quantified. Using standard resolution targets a resolution of 200×1000 pixels is obtained. The suggested method is viewed in scope of modern CCD cameras operating in the near...... CCD detectors. Furthermore, we discuss the exceptionally good depth of field possible for imaging systems based on the proposed method....

  3. Design of a cholesteric liquid crystal cell for a high-transmittance light shutter

    Science.gov (United States)

    Yu, Byeong-Hun; Huh, Jae-Won; Yoon, Tae-Hoon

    2014-02-01

    Recently, active studies on a transparent organic light-emitting diode (OLED) are in progress as a next generation display. However, since it is not possible to obtain a dark state using a transparent OLED, it exhibits poor visibility. This inevitable problem can be solved by placing a light shutter behind a transparent OLED display. In this paper, we propose a light shutter using dye-doped liquid crystals (LCs) whose Bragg reflection wavelength is chosen to be infrared by controlling the pitch of cholesteric liquid crystals (ChLCs). The proposed light shutter is switchable between the dark planar state and the transparent homeotropic state. The proposed light shutter has the advantages of the high transmittance, low operation voltage, and easy fabrication process compared with previous light shutter devices using liquid crystals. It is expected that the proposed light shutter can be applied to realize high visibility transparent OLEDs and emerging smart windows.

  4. Designing High Efficient Solar Powered OLED Lighting Systems

    DEFF Research Database (Denmark)

    Ploug, Rasmus Overgaard; Poulsen, Peter Behrensdorff; Thorsteinsson, Sune

    2016-01-01

    for the 10 Wp version. Furthermore, we present measurements of state-of-the-art commercial available OLED with regards to the luminous flux, luminous efficacy, luminance homogeneity, temperature dependency and IV characteristic of the OLED panels. In addition, solar powered OLED product concepts are proposed.......OLEDs used in solar powered lighting applications is a market of the future. This paper reports the development of electronic Three-Port-Converters for PV OLED product integration in the low-power area respectively for 1-10 Wp and 10-50 Wp with a peak efficiency of 97% at 1.8 W of PV power...

  5. Green Fluorescent Organic Light Emitting Device with High Luminance

    Directory of Open Access Journals (Sweden)

    Ning YANG

    2014-06-01

    Full Text Available In this work, we fabricated the small molecule green fluorescent bottom-emission organic light emitting device (OLED with the configuration of glass substrate/indium tin oxide (ITO/Copper Phthalocyanine (CuPc 25 nm/ N,N’-di(naphthalen-1-yl-N,N’-diphenyl-benzidine (NPB 45 nm/ tris(8-hydroxyquinoline aluminium (Alq3 60 nm/ Lithium fluoride (LiF 1 nm/Aluminum (Al 100 nm where CuPc and NPB are the hole injection layer and the hole transport layer, respectively. CuPc is introduced in this device to improve carrier injection and efficiency. The experimental results indicated that the turn-on voltage is 2.8 V with a maximum luminance of 23510 cd/m2 at 12 V. The maximum current efficiency and power efficiency are 4.8 cd/A at 100 cd/m2 and 4.2 lm/W at 3 V, respectively. The peak of electroluminance (EL spectrum locates at 530 nm which is typical emission peak of green light. In contrast, the maximum current efficiency and power efficiency of the device without CuPc are only 4.0 cd/A at 100 mA/cm2 and 4.2 lm/W at 3.6 V, respectively.

  6. Microdischarge Array Flexible Light Source for High-Efficiency Irradiation of Spaced-Based Crops Project

    Data.gov (United States)

    National Aeronautics and Space Administration — It is desirable to develop a high-efficiency lighting source for large-area irradiation of space-based crops. The key requirements for such a system include high...

  7. Overexpression of glycolate oxidase confers improved photosynthesis under high light and high temperature in rice

    Directory of Open Access Journals (Sweden)

    Li-Li Cui

    2016-08-01

    Full Text Available While glycolate oxidase (GLO is well known as a key enzyme for the photorespiratory metabolism in plants, its physiological function and mechanism remains to be further clarified. Our previous studies have shown that suppression of GLO in rice leads to stunted growth and inhibited photosynthesis (Pn which is positively and linearly correlated with decreased GLO activities. It is, therefore, of interest to further understand whether photosynthesis can be improved when GLO is up-regulated? In this study, four independent overexpression rice lines, with gradient increases in GLO activity, were generated and functionally analyzed. Phenotypic observations showed that the growth could be improved when GLO activities were increased by 60% or 100%, whereas reduced growth was noticed when the activity was further increased by 150% or 210%. As compared with WT plants, all the overexpression plants exhibited significantly improved photosynthesis under conditions of high light and high temperature, but not under normal conditions. In addition, the overexpression plants were more resistant to the MV-induced photooxidative stress. It was further demonstrated that the antioxidant enzymes, and the antioxidant metabolite glutathione was not significantly altered in the overexpression plants. In contrast, H2O2 and salicylic acid (SA were correspondingly induced upon the GLO overexpression. Taken together, the results suggest that GLO may play an important role for plants to cope with high light and high temperature, and that H2O2 and SA may serve as signaling molecules to trigger stress defense responses but antioxidant reactions appear not to be involved in the defense.

  8. Risk of retina damage from high intensity light sources

    Energy Technology Data Exchange (ETDEWEB)

    Pollak, V.A.; Romanchuk, K.G.

    1980-05-01

    The risk of thermal damage to the retina of the eye by exposure to excesive light intensities from continuous and pulsed man-made sources is discussed. The probability of injury increases, the larger the radiant power absorbed by the retina and the smaller the size of the retinal image of the source. A method of estimating the temperature increase of the immediately affected area of the retina is presented. The time constants involved are also briefly considered. Using numerical values from literature for the relevant parameters of the eye, threshold values for a variety of conditions can be established. Below these values little risk of retina damage should exist. The degree of hazard when these values are exceeded depends upon the circumstances. A case study of a welding accident showed good agreement between the conclusions of the theoretical analysis and clinical findings.

  9. Method to generate high efficient devices which emit high quality light for illumination

    Science.gov (United States)

    Krummacher, Benjamin C.; Mathai, Mathew; Choong, Vi-En; Choulis, Stelios A.

    2009-06-30

    An electroluminescent apparatus includes an OLED device emitting light in the blue and green spectrums, and at least one down conversion layer. The down conversion layer absorbs at least part of the green spectrum light and emits light in at least one of the orange spectra and red spectra.

  10. Light limitation of primary production in high latitude reservoirs

    Directory of Open Access Journals (Sweden)

    J. Sahlberg

    2005-01-01

    Full Text Available To explore the effects of vertical mixing on the primary production in a northern reservoir, a Lagrangian particle dispersion model was coupled to a 1-D reservoir model where the vertical mixing was calculated using a k-ε model together with an empirically-based deep-water eddy viscosity. The primary production of each phytoplankton cell is assumed to be a function of the ambient light and not to be nutrient limited. The photoadaption follows first-order kinetics where the photoadaptive variables, a, b, and Pm, describe the coefficients of the photosynthesis-irradiance curve. The model is applied to the northern reservoir Akkajaure, which is strongly regulated with a mean and maximum depth of 30 m and 100 m respectively. Based on the release of 1000 particles (plankton, the model calculated the mean primary production of each plankton, during four different growing seasons. Vertical mixing has a substantial effect on the vertical distribution of phytoplankton and, thus, on the primary production in a reservoir. It was found that primary production was greater in a cold summer with weak stratification than in a warm summer when the reservoir was more stratified.

  11. Blue light hazard optimization for white light-emitting diode sources with high luminous efficacy of radiation and high color rendering index

    Science.gov (United States)

    Zhang, Jingjing; Guo, Weihong; Xie, Bin; Yu, Xingjian; Luo, Xiaobing; Zhang, Tao; Yu, Zhihua; Wang, Hong; Jin, Xing

    2017-09-01

    Blue light hazard of white light-emitting diodes (LED) is a hidden risk for human's photobiological safety. Recent spectral optimization methods focus on maximizing luminous efficacy and improving color performances of LEDs, but few of them take blue hazard into account. Therefore, for healthy lighting, it's urgent to propose a spectral optimization method for white LED source to exhibit low blue light hazard, high luminous efficacy of radiation (LER) and high color performances. In this study, a genetic algorithm with penalty functions was proposed for realizing white spectra with low blue hazard, maximal LER and high color rendering index (CRI) values. By simulations, white spectra from LEDs with low blue hazard, high LER (≥297 lm/W) and high CRI (≥90) were achieved at different correlated color temperatures (CCTs) from 2013 K to 7845 K. Thus, the spectral optimization method can be used for guiding the fabrication of LED sources in line with photobiological safety. It is also found that the maximum permissible exposure duration of the optimized spectra increases by 14.9% than that of bichromatic phosphor-converted LEDs with equal CCT.

  12. Vendors Future: Northern Light--Delivering High-Quality Content to a Large Internet Audience.

    Science.gov (United States)

    Wiggins, Richard

    1997-01-01

    Describes a Web-based information service, Northern Light, which demonstrates a new paradigm for serving large populations of users and delivering high-quality content on topics both general and narrow. Discusses performance of the search engine, search syntax, Northern Light's special collection, and pricing. (AEF)

  13. High power laser-driven ceramic phosphor plate for outstanding efficient white light conversion in application of automotive lighting.

    Science.gov (United States)

    Song, Young Hyun; Ji, Eun Kyung; Jeong, Byung Woo; Jung, Mong Kwon; Kim, Eun Young; Yoon, Dae Ho

    2016-08-09

    We report on Y3Al5O12: Ce(3+) ceramic phosphor plate (CPP) using nano phosphor for high power laser diode (LD) application for white light in automotive lighting. The prepared CPP shows improved luminous properties as a function of Ce(3+) concentration. The luminous properties of the Y3Al5O12: Ce(3+) CPP nano phosphor are improved when compared to the Y3Al5O12: Ce(3+) CPP with bulk phosphor, and hence, the luminous emittance, luminous flux, and conversion efficiency are improved. The Y3Al5O12: Ce(3+) CPP with an optimal Ce(3+) content of 0.5 mol % shows 2733 lm/mm(2) value under high power blue radiant flux density of 19.1 W/mm(2). The results indicate that Y3Al5O12: Ce(3+) CPP using nano phosphor can serve as a potential material for solid-state laser lighting in automotive applications.

  14. Shedding Light on Filovirus Infection with High-Content Imaging

    Directory of Open Access Journals (Sweden)

    Rekha G. Panchal

    2012-08-01

    Full Text Available Microscopy has been instrumental in the discovery and characterization of microorganisms. Major advances in high-throughput fluorescence microscopy and automated, high-content image analysis tools are paving the way to the systematic and quantitative study of the molecular properties of cellular systems, both at the population and at the single-cell level. High-Content Imaging (HCI has been used to characterize host-virus interactions in genome-wide reverse genetic screens and to identify novel cellular factors implicated in the binding, entry, replication and egress of several pathogenic viruses. Here we present an overview of the most significant applications of HCI in the context of the cell biology of filovirus infection. HCI assays have been recently implemented to quantitatively study filoviruses in cell culture, employing either infectious viruses in a BSL-4 environment or surrogate genetic systems in a BSL-2 environment. These assays are becoming instrumental for small molecule and siRNA screens aimed at the discovery of both cellular therapeutic targets and of compounds with anti-viral properties. We discuss the current practical constraints limiting the implementation of high-throughput biology in a BSL-4 environment, and propose possible solutions to safely perform high-content, high-throughput filovirus infection assays. Finally, we discuss possible novel applications of HCI in the context of filovirus research with particular emphasis on the identification of possible cellular biomarkers of virus infection.

  15. Photorespiration participates in the assimilation of acetate in Chlorella sorokiniana under high light.

    Science.gov (United States)

    Xie, Xiujun; Huang, Aiyou; Gu, Wenhui; Zang, Zhengrong; Pan, Guanghua; Gao, Shan; He, Linwen; Zhang, Baoyu; Niu, Jianfeng; Lin, Apeng; Wang, Guangce

    2016-02-01

    The development of microalgae on an industrial scale largely depends on the economic feasibility of mass production. High light induces productive suspensions during cultivation in a tubular photobioreactor. Herein, we report that high light, which inhibited the growth of Chlorella sorokiniana under autotrophic conditions, enhanced the growth of this alga in the presence of acetate. We compared pigments, proteomics and the metabolic flux ratio in C. sorokiniana cultivated under high light (HL) and under low light (LL) in the presence of acetate. Our results showed that high light induced the synthesis of xanthophyll and suppressed the synthesis of chlorophylls. Acetate in the medium was exhausted much more rapidly in HL than in LL. The data obtained from LC-MS/MS indicated that high light enhanced photorespiration, the Calvin cycle and the glyoxylate cycle of mixotrophic C. sorokiniana. The results of metabolic flux ratio analysis showed that the majority of the assimilated carbon derived from supplemented acetate, and photorespiratory glyoxylate could enter the glyoxylate cycle. Based on these data, we conclude that photorespiration provides glyoxylate to speed up the glyoxylate cycle, and releases acetate-derived CO2 for the Calvin cycle. Thus, photorespiration connects the glyoxylate cycle and the Calvin cycle, and participates in the assimilation of supplemented acetate in C. sorokiniana under high light. © 2015 Institute of Oceanography, Chinese Academy of Sciences (IOCAS). New Phytologist © 2015 New Phytologist Trust.

  16. High intensity Discharge lighting; Alumbrado de alta intensidad de descarga

    Energy Technology Data Exchange (ETDEWEB)

    Mendoza E, Ernesto J. [Manufacturera de Reactores, S. A., Mexico, D. F. (Mexico)

    1993-12-31

    This paper gets into contact with some fundamentals in the operation of high discharge intensity lamps. There are useful definitions, as well as the study of the operation of high pressure sodium lamps and of metallic additives operating at less than nominal power. [Espanol] Este trabajo pone al lector en contacto con algunos fundamentos de la operacion de las lamparas de alta intensidad de descarga (HID). Se encuentra con definiciones utiles, asi como el estudio de la operacion de las lamparas de sodio en alta presion y de aditivos metalicos operando a una potencia menor que la nominal.

  17. CdSe/ZnS quantum dot films for high performance flexible lighting and display applications.

    Science.gov (United States)

    Altintas, Yemliha; Genc, Sinan; Talpur, Mohammad Younis; Mutlugun, Evren

    2016-07-22

    Colloidal quantum dots have attracted significant interest in recent years for lighting and display applications and have recently appeared in high-end market products. The integration of quantum dots with light emitting diodes has made them promising candidates for superior lighting applications with tunable optical characteristics. In this work we propose and demonstrate high quality colloidal quantum dots in their novel free-standing film forms to allow high quality white light generation to address flexible lighting and display applications. High quality quantum dots have been characterized using transmission electron microscopy, x-ray diffraction, x-ray photoelectron spectroscopy, steady state and time resolved photoluminescence and dynamic light scattering methods. The engineering of colloidal quantum dot composition and its optical properties in stand-alone film form has led to the experimentally high NTSC color gamut of 122.5 (CIE-1931) for display applications, color rendering index of 88.6, luminous efficacy of optical radiation value of 290 lm/Wopt and color temperature of 2763 K for lighting applications.

  18. Effect of light-tip distance on the shear bond strengths of resin-modified glass ionomer cured with high-intensity halogen, light-emitting diode, and plasma arc lights.

    Science.gov (United States)

    Sfondrini, Maria Francesca; Cacciafesta, Vittorio; Scribante, Andrea; Boehme, Andreas; Jost-Brinkmann, Paul-Georg

    2006-04-01

    The purpose of this study was to assess the effect of light-tip distance on the shear bond strength and the failure site of brackets cured with 3 light-curing units (high-intensity halogen, light-emitting diode, and plasma arc). One hundred thirty-five bovine mandibular permanent incisors were randomly allocated to 9 groups of 15 specimens each. Stainless steel brackets (Victory Series, Unitek/3M, Monrovia, Calif) were bonded with a resin-modified glass-ionomer (Fuji Ortho LC, GC Europe, Leuven, Belgium) to the teeth, and each curing light was tested at 3 distances from the bracket: 0, 3, and 6 mm. After bonding, all samples were stored in distilled water at room temperature for 24 hours and subsequently tested for shear bond strength. When the 3 light-curing units were compared at a light-tip distance of 0mm, they showed no significantly different shear bond strengths. At a light-tip distance of 3 mm, no significant differences were found between the halogen and plasma arc lights, but both lights showed significantly higher shear bond strengths than the light-emitting diode light. At a light-tip distance of 6 mm, no significant differences were found between the halogen and light-emitting diode lights, but both showed significantly lower bond strengths than the plasma arc light. When the effect of the light-tip distance on each light-curing unit was evaluated, the halogen and light-emitting diode lights showed no significant differences among the 3 distances. However, the plasma arc light produced significantly higher shear bond strengths at a greater light-tip distance. No significant differences were found among the adhesive remnant index scores of the various groups, except with the LED light at a distance of 3 mm. In hard-to-reach areas, the plasma arc curing light is suggested for optimal curing efficiency.

  19. Heat transfer and structure stress analysis of micro packaging component of high power light emitting diode

    Directory of Open Access Journals (Sweden)

    Hsu Chih-Neng

    2013-01-01

    Full Text Available This paper focuses on the heat transfer and structural stress analysis of the micro- scale packaging structure of a high-power light emitting diode. The thermal-effect and thermal-stress of light emitting diode are determined numerically. Light emitting diode is attached to the silicon substrate through the wire bonding process by using epoxy as die bond material. The silicon substrate is etched with holes at the bottom and filled with high conductivity copper material. The chip temperature and structure stress increase with input power consumption. The micro light emitting diode is mounted on the heat sink to increase the heat dissipation performance, to decrease chip temperature, to enhance the material structure reliability and safety, and to avoid structure failure as well. This paper has successfully used the finite element method to the micro-scale light emitting diode heat transfer and stress concentration at the edges through etched holes.

  20. High-Redshift galaxies light from the early universe

    CERN Document Server

    Appenzeller, Immo

    2008-01-01

    This book provides a comprehensive account of the scientific results on high-redshift galaxies accumulated during the past ten years. Apart from summarizing and critically discussing the wealth of observational data, the observational methods which made it possible to study these very distant and extremely faint objects are described in detail. Moreover, the technical feasibilities and physical limitations for existing and for future ground-based and space-based telescopes are discussed. Thus, apart from summarizing the knowledge accumulated so far, the book is designed as a tool for planning future observational and instrumental programs and projects. In view of the potential importance of the observational results of the high-redshift universe for basic physics the book is written for astronomers as well as for physicists without prior astronomical knowledge. For this purpose it contains introductory chapters describing the basic concepts and notations used in modern astronomy and a brief overview of the pr...

  1. High-resolution full-field spatial coherence gated optical tomography using monochromatic light source

    Science.gov (United States)

    Srivastava, Vishal; Nandy, Sreyankar; Singh Mehta, Dalip

    2013-09-01

    We demonstrate dispersion free, high-resolution full-field spatial coherence gated optical tomography using spatially incoherent monochromatic light source. Spatial coherence properties of light source were synthesized by means of combining a static diffuser and vibrating multi mode fiber bundle. Due to low spatial coherence of light source, the axial resolution of the system was achieved similar to that of conventional optical coherence tomography which utilizes low temporal coherence. Experimental results of fringe visibility versus optical path difference are presented for varying numerical apertures objective lenses. High resolution optically sectioned images of multilayer onion skin, and red blood cells are presented.

  2. Polarization holograms allow highly efficient generation of complex light beams.

    Science.gov (United States)

    Ruiz, U; Pagliusi, P; Provenzano, C; Volke-Sepúlveda, K; Cipparrone, Gabriella

    2013-03-25

    We report a viable method to generate complex beams, such as the non-diffracting Bessel and Weber beams, which relies on the encoding of amplitude information, in addition to phase and polarization, using polarization holography. The holograms are recorded in polarization sensitive films by the interference of a reference plane wave with a tailored complex beam, having orthogonal circular polarizations. The high efficiency, the intrinsic achromaticity and the simplicity of use of the polarization holograms make them competitive with respect to existing methods and attractive for several applications. Theoretical analysis, based on the Jones formalism, and experimental results are shown.

  3. High resolution measurement of light in terrestrial ecosystems using photodegrading dyes.

    Directory of Open Access Journals (Sweden)

    Javier Roales

    Full Text Available Incoming solar radiation is the main determinant of terrestrial ecosystem processes, such as primary production, litter decomposition, or soil mineralization rates. Light in terrestrial ecosystems is spatially and temporally heterogeneous due to the interaction among sunlight angle, cloud cover and tree-canopy structure. To integrate this variability and to know light distribution over time and space, a high number of measurements are needed, but tools to do this are usually expensive and limited. An easy-to-use and inexpensive method that can be used to measure light over time and space is needed. We used two photodegrading fluorescent organic dyes, rhodamine WT (RWT and fluorescein, for the quantification of light. We measured dye photodegradation as the decrease in fluorescence across an irradiance gradient from full sunlight to deep shade. Then, we correlated it to accumulated light measured with PAR quantum sensors and obtained a model for this behavior. Rhodamine WT and fluorescein photodegradation followed an exponential decay curve with respect to accumulated light. Rhodamine WT degraded slower than fluorescein and remained unaltered after exposure to temperature changes. Under controlled conditions, fluorescence of both dyes decreased when temperatures increased, but returned to its initial values after cooling to the pre-heating temperature, indicating no degradation. RWT and fluorescein can be used to measure light under a varying range of light conditions in terrestrial ecosystems. This method is particularly useful to integrate solar radiation over time and to measure light simultaneously at different locations, and might be a better alternative to the expensive and time consuming traditional light measurement methods. The accuracy, low price and ease of this method make it a powerful tool for intensive sampling of large areas and for developing high resolution maps of light in an ecosystem.

  4. Dawn song in natural and artificial continuous day: Light pollution affects songbirds at high latitudes.

    Science.gov (United States)

    Derryberry, Elizabeth P

    2017-10-01

    In Focus: Da Silva, A., & Kempenaers, B. (2017). Singing from North to South: Latitudinal variation in timing of dawn singing under natural and artificial light conditions. Journal of Animal Ecology, 86, 1286-1297. doi: 10.1111/1365-2656.12739 Satellite images of the world at night show bright dots connected by glowing lines crisscrossing the globe. As these connect-the-dots become brighter and expand into more and more remote regions, much of the flora and fauna of the world are experiencing evolutionarily unprecedented levels of light at night. Light cues are essential to most physiological and behavioural processes, and so the need to measure the effects of light pollution on these processes is critical. In this issue, Da Silva and Kempenaers take on this task using an important reproductive behaviour in songbirds-dawn song. The geographic, temporal and taxonomic breadth of sampling in this study allows for a close examination of a potentially complex interaction between light pollution and natural variation in the behaviour of dawn singing across latitude, season and species. Their extensive dataset highlights complexity in how songbirds respond to light pollution. Although light pollution has a strong effect on the timing of dawn song, not all songbirds respond the same way to light pollution, and the effects of light pollution vary with changes in natural light levels. Early dawn singers show more flexibility in the timing of dawn song across the season and across latitudes than late dawn singers, and also appear less affected by light pollution at high latitudes than are late dawn singers. These findings suggest that not all songbirds are responding to artificial continuous daylight as they do to natural continuous daylight, highlighting the general need to measure the fitness effects of light pollution. © 2017 The Author. Journal of Animal Ecology © 2017 British Ecological Society.

  5. Lighting Systems For High Speed Photography Applying Special Metal Halide Discharge Lamps

    Science.gov (United States)

    Gillum, Keith M.; Steuernagel, K. H.

    1983-03-01

    High speed photography requires, in addition to a good color quality of the light source, a very high level of illumination. Conventional lighting systems utilizing incandescent lamps or other metal halide lamp types has inherent problems of inefficient light output or poor color quality. Heat generated by incandescent lamps and the power these sources require drive up operating and installation costs. A most economical and practical solution was devised by using the metal halide discharge lamp developed by OSRAM, GmbH of Munich, West Germany. This lamp trade marked the HMITM Metallogen was primarily developed for the needs of the television and motion picture film industry. Due to their high efficiency and other consistent operating qualities these lamps also fulfill the needs of high speed photography, e.g. in crash test facilities, when special engineering activities are carried out. The OSRAM HMITM lamp is an AC discharge metal halide lamp with rare earth additives to increase both the efficiency and light output qualities. Since the lamp is an AC source, a special method had to be developed to overcome the strobing effect, which is normal for AC lamps given their modulated light output, when used with high speed cameras, (e.g. with >1000 fps). This method is based on an increased frequency for the lamp supply voltage coupled with a mix of the light output achieved using a multiphase mains power supply. First developed in 1977, this system using the OSRAM HMITM lamps was installed in a crash test facility of a major automotive manufacturer in West Germany. The design resulted in the best lighting and performance ever experienced. Since that time several other motor companies have made use of this breakthrough. Industrial and scientific users are now considering additional applications use of this advanced high speed lighting system.

  6. Use of high-radiant flux, high-resolution DMD light engines in industrial applications

    Science.gov (United States)

    Müller, Alexandra; Ram, Surinder

    2014-03-01

    The field of application of industrial projectors is growing day by day. New Digital Micromirror Device (DMD) - based applications like 3D printing, 3D scanning, Printed Circuit Board (PCB) board printing and others are getting more and more sophisticated. The technical demands for the projection system are rising as new and more stringent requirements appear. The specification for industrial projection systems differ substantially from the ones of business and home beamers. Beamers are designed to please the human eye. Bright colors and image enhancement are far more important than uniformity of the illumination or image distortion. The human eye, followed by the processing of the brain can live with quite high intensity variations on the screen and image distortion. On the other hand, a projector designed for use in a specialized field has to be tailored regarding its unique requirements in order to make no quality compromises. For instance, when the image is projected onto a light sensitive resin, a good uniformity of the illumination is crucial for good material hardening (curing) results. The demands on the hardware and software are often very challenging. In the following we will review some parameters that have to be considered carefully for the design of industrial projectors in order to get the optimum result without compromises.

  7. Exciplex-Forming Cohost for High Efficiency and High Stability Phosphorescent Organic Light-Emitting Diodes.

    Science.gov (United States)

    Shih, Chun-Jen; Lee, Chih-Chien; Chen, Ying-Hao; Biring, Sajal; Kumar, Gautham; Yeh, Tzu-Hung; Sen, Somaditya; Liu, Shun-Wei; Wong, Ken-Tsung

    2018-01-17

    An exciplex forming cohost system is employed to achieve a highly efficient organic light-emitting diode (OLED) with good electroluminescent lifetime. The exciplex is formed at the interfacial contact of a conventional star-shaped carbazole hole-transporting material, 4,4',4″-tris(N-carbazolyl)-triphenylamine (TCTA), and a triazine electron-transporting material, 2,4,6-tris[3-(1H-pyrazol-1-yl)phenyl]-1,3,5-triazine (3P-T2T). The excellent combination of TCTA and 3P-T2T is applied as the cohost of a common green phosphorescent emitter with almost zero energy loss. When Ir(ppy)2(acac) is dispersed in such exciplex cohost system, OLED device with maximum external quantum efficiency of 29.6%, the ultrahigh power efficiency of 147.3 lm/W, and current efficiency of 107 cd/A were successfully achieved. More importantly, the OLED device showed a low-efficiency roll-off and an operational lifetime (τ80) of ∼1020 min with the initial brightness of 2000 cd/m2, which is 56 times longer than the reference device. The significant difference of device stability was attributed to the degradation of exciplex system for energy transfer process, which was investigated by the photoluminescence aging measurement at room temperature and 100 K, respectively.

  8. Automated high throughput whole slide imaging using area sensors, flash light illumination and solid state light engine.

    Science.gov (United States)

    Varga, Viktor Sebestyén; Molnár, Béla; Virág, Tibor

    2012-01-01

    Whole Slide Imagers or digital slide scanners have developed very rapidly in the last 8 years and went through three generations. Third generation instruments have just reached the market which have the stability and throughput to be used for routine clinical work. We describe in this article the technical background and reasoning behind engineering decisions we made during the development of 3DHISTECH's 3rd generation combined brightfield and fluorescent scanner. The Panoramic 250 FLASH utilizes Plan-Apochromat 20x and 40x objectives, a 2 megapixel 3CCD camera for brightfield and a monochrome scientific CMOS camera for fluorescent scanning. A solid state light engine for fluorescent and a strobe light for bright field illumination are used. The system can scan 1cm2 including focusing at 45x resolution in 1 minute. It can scan a well stained DAPI, FITC, TRIC, 1cm2 fluorescent slide in 11 minutes. It can load and scan 250 slides in walk away mode. Using the latest camera technology and electronics, state of the art computer and standard microscope optical components high throughput high quality whole slide imaging is feasible and is sufficient for most of the routine diagnostic work. Extended depth of field and Z-stack scanning is possible with the use of area scan technology.

  9. A high precision flat crystal spectrometer compatible for ultra-high vacuum light source

    Science.gov (United States)

    Yang, Y.; Xiao, J.; Lu, D.; Shen, Y.; Yao, K.; Chen, C.; Hutton, R.; Zou, Y.

    2017-11-01

    We report on a flat crystal spectrometer (FCS) featuring a differently pumped rotary feedthrough and double detectors connected to a crystal chamber by extendable bellows built at the Shanghai EBIT Laboratory. It was designed to overcome defects such as oil contamination, little distance from the detector to the crystal and others of an early FCS equipped at the same laboratory, but still keeps a large detectable angle range of detectors and brings new features and functions such as the Bond method measurement and double-crystal measurement which are based on the two-detector and large bellow design. This new FCS could cover an energy range of measurable photons from 570 eV to 10 keV and reach a vacuum better than 6 × 10-10 Torr and thus is compatible for coupling directly to ultra-high vacuum light sources. Off-line tests of the FCS were undertaken where Kα x-rays from solid titanium were measured and analyzed. Measurements of transitions in He-like argon ions were performed when the spectrometer was directly connected to Shanghai EBIT, and the width of the x-ray source was monitored simultaneously using an x-ray slit imaging system. An observed spectral line broadening was 0.869 eV corresponding to a resolving power of 3600, including Doppler broadening of the x-ray source. Taking account of the measured source width, we made simulations using the SHADOW 3 code and got a nominal resolving power of 6500 for the spectrometer. This high nominal resolving power is due to a longer distance from the crystal to the detector, comparing with that in the early FCS.

  10. An integrated analysis of molecular acclimation to high light in the marine diatom Phaeodactylum tricornutum.

    Directory of Open Access Journals (Sweden)

    Marianne Nymark

    Full Text Available Photosynthetic diatoms are exposed to rapid and unpredictable changes in irradiance and spectral quality, and must be able to acclimate their light harvesting systems to varying light conditions. Molecular mechanisms behind light acclimation in diatoms are largely unknown. We set out to investigate the mechanisms of high light acclimation in Phaeodactylum tricornutum using an integrated approach involving global transcriptional profiling, metabolite profiling and variable fluorescence technique. Algae cultures were acclimated to low light (LL, after which the cultures were transferred to high light (HL. Molecular, metabolic and physiological responses were studied at time points 0.5 h, 3 h, 6 h, 12 h, 24 h and 48 h after transfer to HL conditions. The integrated results indicate that the acclimation mechanisms in diatoms can be divided into an initial response phase (0-0.5 h, an intermediate acclimation phase (3-12 h and a late acclimation phase (12-48 h. The initial phase is recognized by strong and rapid regulation of genes encoding proteins involved in photosynthesis, pigment metabolism and reactive oxygen species (ROS scavenging systems. A significant increase in light protecting metabolites occur together with the induction of transcriptional processes involved in protection of cellular structures at this early phase. During the following phases, the metabolite profiling display a pronounced decrease in light harvesting pigments, whereas the variable fluorescence measurements show that the photosynthetic capacity increases strongly during the late acclimation phase. We show that P. tricornutum is capable of swift and efficient execution of photoprotective mechanisms, followed by changes in the composition of the photosynthetic machinery that enable the diatoms to utilize the excess energy available in HL. Central molecular players in light protection and acclimation to high irradiance have been identified.

  11. Production of a diffuse very high reflectivity material for light collection in nuclear detectors

    CERN Document Server

    Pichler, B J; Mirzoyan, R; Weiss, L; Ziegler, S I

    2000-01-01

    A diffuse very high reflectivity material, based on polytetrafluorethylene (PTFE) for optimization of light-collection efficiency has been developed. PTFE powder was used to produce reflector block material. The powder was pressed with 525 kPa in a form and sintered at 375 deg. C. The reflectivity was above 98% within the spectral range from 350 to 1000 nm. The blocks of this material are machinable with saws, drilling and milling machines. The reflector is used as a housing for scintillating crystals in a nuclear medicine application (small animal positron emission tomograph). It is also used as a light collector in very high-energy gamma-ray astrophysicas experiments, HEGRA and MAGIC. The application of this inexpensive, easy to make diffuse reflector may allow the optimization of light collection in a wide range of low-level light-detector configurations.

  12. A high-performance stand-alone solar PV power system for LED lighting

    KAUST Repository

    Huang, B. J.

    2010-06-01

    The present study developed a high-performance solar PV power technology for the LED lighting of a solar home system. The nMPPO (near-Maximum-Power- Point- Operation) design is employed in system design to eliminate MPPT. A feedback control system using pulse width modulation (PWM) technique was developed for battery charging control which can increase the charging capacity by 78%. For high-efficiency lighting, the LED is directly driven by battery using a PWM discharge control to eliminate a DC/DC converter. Two solar-powered LED lighting systems (50W and 100W LED) were built. The long-term outdoor tests have shown that the loss of load probability for full-night lighting requirement is zero for 50W LED and 3.6% for 100W LED. © 2010 IEEE.

  13. A two-dimensional analysis on high light extraction efficiency (LEE) LEDs with asymmetric microstructured substrate

    Science.gov (United States)

    Chen, Chang-Jiang; Zhu, Wenbin; Chao, Ju-Hung; Zhou, Haonan; Yin, Stuart (Shizhuo)

    2017-08-01

    This paper presents a quantitative two-dimensional (2D) analysis on high power GaN light emitting diodes (LEDs) fabricated on asymmetric micro-structured substrates. It is found that the light extraction efficiency (LEE) can be substantially improved from conventional symmetric structure to asymmetric structure. The increase of LEE is mainly dedicated to the increased surface area and better randomization on the direction of transmitted/reflected light, which enhances the escaping probability after multiple reflections. This quantitative 2D analysis lays down a solid foundation for the future quantitative 3D analysis.

  14. High luminous flux from single crystal phosphor-converted laser-based white lighting system

    KAUST Repository

    Cantore, Michael

    2015-12-14

    The efficiency droop of light emitting diodes (LEDs) with increasing current density limits the amount of light emitted per wafer area. Since low current densities are required for high efficiency operation, many LED die are needed for high power white light illumination systems. In contrast, the carrier density of laser diodes (LDs) clamps at threshold, so the efficiency of LDs does not droop above threshold and high efficiencies can be achieved at very high current densities. The use of a high power blue GaN-based LD coupled with a single crystal Ce-doped yttrium aluminum garnet (YAG:Ce) sample was investigated for white light illumination applications. Under CW operation, a single phosphor-converted LD (pc-LD) die produced a peak luminous efficacy of 86.7 lm/W at 1.4 A and 4.24 V and a peak luminous flux of 1100 lm at 3.0 A and 4.85 V with a luminous efficacy of 75.6 lm/W. Simulations of a pc-LD confirm that the single crystal YAG:Ce sample did not experience thermal quenching at peak LD operating efficiency. These results show that a single pc-LD die is capable of emitting enough luminous flux for use in a high power white light illumination system.

  15. Near-infrared organic light-emitting diodes for biosensing with high operating stability

    Science.gov (United States)

    Yamanaka, Takahiko; Nakanotani, Hajime; Hara, Shigeo; Hirohata, Toru; Adachi, Chihaya

    2017-07-01

    We demonstrate highly stable NIR organic light-emitting diodes (OLEDs) based on a system using excitonic energy transfer from thermally activated delay fluorescence molecules to NIR fluorophores. The NIR OLEDs showed an electroluminescence peak at 780 nm and robust operational stability with 2% loss of the initial radiant flux after 1000 h under a constant current density of 10 mA/cm2. The variation of hemoglobin oxygen saturation can be detected using the NIR OLEDs as a light source.

  16. Design and Fluid Dynamic Investigations for a High Performance Light Water Reactor Fuel Assembly

    Science.gov (United States)

    Hofmeister, Jan; Laurin, Eckart; Class, Andreas G.

    2005-11-01

    Within the 5th Framework Program of the European Commission a nuclear light water reactor with supercritical steam conditions has been investigated called High Performance Light Water Reactor (HPLWR). This reactor concept is distinct from conventional light water reactor concepts by the fact, that supercritical water is used to achieve higher core outlet temperatures. The reactor operates with a high system pressure, high heat-up of the coolant within the core, and high outlet temperatures of the coolant resulting in a thermal efficiency of up to 44%. We present the design concept proposed by IKET, and a fluid dynamic problem in the foot piece of the fuel assembly, where unacceptable temperature variations must be omitted.

  17. Solution-processed multilayer small-molecule light-emitting devices with high-efficiency white-light emission

    Science.gov (United States)

    Aizawa, Naoya; Pu, Yong-Jin; Watanabe, Michitake; Chiba, Takayuki; Ideta, Kazushige; Toyota, Naoki; Igarashi, Masahiro; Suzuri, Yoshiyuki; Sasabe, Hisahiro; Kido, Junji

    2014-12-01

    Recent developments in the field of π-conjugated polymers have led to considerable improvements in the performance of solution-processed organic light-emitting devices (OLEDs). However, further improving efficiency is still required to compete with other traditional light sources. Here we demonstrate efficient solution-processed multilayer OLEDs using small molecules. On the basis of estimates from a solvent resistance test of small host molecules, we demonstrate that covalent dimerization or trimerization instead of polymerization can afford conventional small host molecules sufficient resistance to alcohols used for processing upper layers. This allows us to construct multilayer OLEDs through subsequent solution-processing steps, achieving record-high power efficiencies of 36, 52 and 34 lm W-1 at 100 cd m-2 for solution-processed blue, green and white OLEDs, respectively, with stable electroluminescence spectra under varying current density. We also show that the composition at the resulting interface of solution-processed layers is a critical factor in determining device performance.

  18. Orthodontic bracket shear bond strengths produced by two high-power light-emitting diode modes and halogen light.

    Science.gov (United States)

    Türkkahraman, Hakan; Küçükeşmen, H Cenker

    2005-09-01

    The aim of this in vitro study was to compare the shear bond strength of orthodontic brackets cured with two different high-power light-emitting diode (LED) polymerization modes with traditional halogen polymerization. A total of forty-five extracted human premolar teeth were randomly divided into three groups. Each group consisted of 15 teeth mounted in an acrylic block. Following a standard enamel etching protocol, orthodontic brackets were cured on the first group of teeth with fast-mode LED, the second group with soft-start mode LED, and on the last group with a halogen light. After bonding, the shear bond strengths of the brackets were tested with a universal testing machine. The results showed that brackets cured with soft-start mode LED produced the highest shear bond strengths (23.86 +/- 6.20 MPa). No significant difference was found between fast-mode LED (17.14 +/- 5.75 MPa) and the halogen group (17.38 +/- 5.41 MPa) (P > .05). The LED is effective for bonding metal brackets to teeth, and the soft-start mode gives higher bond strengths than the fast mode.

  19. Highly polarized light emission by isotropic quantum dots integrated with magnetically aligned segmented nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Uran, Can; Erdem, Talha; Guzelturk, Burak [Department of Electrical and Electronics Engineering, Department of Physics, and UNAM - National Nanotechnology Research Center, Institute of Materials Science and Nanotechnology, Bilkent University, Ankara 06800 (Turkey); Perkgöz, Nihan Kosku [Department of Electrical and Electronics Engineering, Department of Physics, and UNAM - National Nanotechnology Research Center, Institute of Materials Science and Nanotechnology, Bilkent University, Ankara 06800 (Turkey); Department of Electrical and Electronics Engineering, Faculty of Engineering, Anadolu University, Eskisehir 26555 (Turkey); Jun, Shinae; Jang, Eunjoo [Inorganic Material Laboratory, Material Research Center, Samsung Advanced Institute of Technology, Samsung Electronics Co., 130 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do 443-803 (Korea, Republic of); Demir, Hilmi Volkan, E-mail: volkan@stanfordalumni.org [Department of Electrical and Electronics Engineering, Department of Physics, and UNAM - National Nanotechnology Research Center, Institute of Materials Science and Nanotechnology, Bilkent University, Ankara 06800 (Turkey); Luminous Center of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, School of Physical and Materials Sciences, Nanyang Technological University, Singapore, Singapore 639798 (Singapore)

    2014-10-06

    In this work, we demonstrate a proof-of-concept system for generating highly polarized light from colloidal quantum dots (QDs) coupled with magnetically aligned segmented Au/Ni/Au nanowires (NWs). Optical characterizations reveal that the optimized QD-NW coupled structures emit highly polarized light with an s-to p-polarization (s/p) contrast as high as 15:1 corresponding to a degree of polarization of 0.88. These experimental results are supported by the finite-difference time-domain simulations, which demonstrate the interplay between the inter-NW distance and the degree of polarization.

  20. High light intensity protects photosynthetic apparatus of pea plants against exposure to lead.

    Science.gov (United States)

    Romanowska, E; Wróblewska, B; Drozak, A; Siedlecka, M

    2006-01-01

    The electron transport rates and coupling factor activity in the chloroplasts; adenylate contents, rates of photosynthesis and respiration in the leaves as well as activity of isolated mitochondria were investigated in Pisum sativum L. leaves of plants grown under low or high light intensity and exposed after detachment to 5 mM Pb(NO(3))(2). The presence of Pb(2+) reduced rate of photosynthesis in the leaves from plants grown under the high light (HL) and low light (LL) conditions, whereas the respiration was enhanced in the leaves from HL plants. Mitochondria from Pb(2+) treated HL-leaves oxidized glycine at a higher rate than those isolated from LL leaves. ATP content in the Pb-treated leaves increased to a greater extend in the HL than LL grown plants. Similarly ATP synthase activity increased markedly when chloroplasts isolated from control and Pb-treated leaves of HL and LL grown plants were subjected to high intensity light. The presence of Pb ions was found inhibit ATP synthase activity only in chloroplasts from LL grown plants or those illuminated with low intensity light. Low light intensity during growth also lowered PSI electron transport rates and the Pb(2+) induced changes in photochemical activity of this photosystem were visible only in the chloroplasts isolated from LL grown plants. The activity of PSII was influenced by Pb ions on similar manner in both light conditions. This study demonstrates that leaves from plants grown under HL conditions were more resistant to lead toxicity than those obtained from the LL grown plants. The data indicate that light conditions during growth might play a role in regulation of photosynthetic and respiratory energy conservation in heavy metal stressed plants by increasing the flexibility of the stoichiometry of ATP to ADP production.

  1. Novel Low Cost Organic Vapor Jet Printing of Striped High Efficiency Phosphorescent OLEDs for White Lighting

    Energy Technology Data Exchange (ETDEWEB)

    Mike Hack

    2008-12-31

    In this program, Universal Display Corporation and University of Michigan proposed to integrate three innovative concepts to meet the DOE's Solid State Lighting (SSL) goals: (1) high-efficiency phosphorescent organic light emitting device (PHOLED{trademark}) technology, (2) a white lighting design that is based on a series of red, green and blue OLED stripes, and (3) the use of a novel cost-effective, high rate, mask-less deposition process called organic vapor jet printing (OVJP). Our PHOLED technology offers up to four-times higher power efficiency than other OLED approaches for general lighting. We believe that one of the most promising approaches to maximizing the efficiency of OLED lighting sources is to produce stripes of the three primary colors at such a pitch (200-500 {mu}m) that they appear as a uniform white light to an observer greater than 1 meter (m) away from the illumination source. Earlier work from a SBIR Phase 1 entitled 'White Illumination Sources Using Striped Phosphorescent OLEDs' suggests that stripe widths of less than 500 {mu}m appear uniform from a distance of 1m without the need for an external diffuser. In this program, we intend to combine continued advances in this PHOLED technology with the striped RGB lighting design to demonstrate a high-efficiency, white lighting source. Using this background technology, the team has focused on developing and demonstrating the novel cost-effective OVJP process to fabricate these high-efficiency white PHOLED light sources. Because this groundbreaking OVJP process is a direct printing approach that enables the OLED stripes to be printed without a shadow mask, OVJP offers very high material utilization and high throughput without the costs and wastage associated with a shadow mask (i.e. the waste of material that deposits on the shadow mask itself). As a direct printing technique, OVJP also has the potential to offer ultra-high deposition rates (> 1,000 Angstroms/second) for any size or

  2. N-formylkynurenine as a marker of high light stress in photosynthesis.

    Science.gov (United States)

    Dreaden, Tina M; Chen, Jun; Rexroth, Sascha; Barry, Bridgette A

    2011-06-24

    Photosystem II (PSII) is the membrane protein complex that catalyzes the photo-induced oxidation of water at a manganese-calcium active site. Light-dependent damage and repair occur in PSII under conditions of high light stress. The core reaction center complex is composed of the D1, D2, CP43, and CP47 intrinsic polypeptides. In this study, a new chromophore formed from the oxidative post-translational modification of tryptophan is identified in the CP43 subunit. Tandem mass spectrometry peptide sequencing is consistent with the oxidation of the CP43 tryptophan side chain, Trp-365, to produce N-formylkynurenine (NFK). Characterization with ultraviolet visible absorption and ultraviolet resonance Raman spectroscopy supports this assignment. An optical assay suggests that the yield of NFK increases 2-fold (2.2 ± 0.5) under high light illumination. A concomitant 2.4 ± 0.5-fold decrease is observed in the steady-state rate of oxygen evolution under the high light conditions. NFK is the product formed from reaction of tryptophan with singlet oxygen, which can be produced under high light stress in PSII. Reactive oxygen species reactions lead to oxidative damage of the reaction center, D1 protein turnover, and inhibition of electron transfer. Our results are consistent with a role for the CP43 NFK modification in photoinhibition.

  3. High efficiency asymmetric directional coupler for slow light slot photonic crystal waveguides.

    Science.gov (United States)

    Xu, Yameng; Caer, Charles; Gao, Dingshan; Cassan, Eric; Zhang, Xinliang

    2014-05-05

    An asymmetric directional coupler scheme for the efficient injection of light into slow light slot photonic crystal waveguide modes is proposed and investigated using finite-difference time-domain simulation. Coupling wavelengths can be flexibly controlled by the geometrical parameters of a side-coupled subwavelength corrugated strip waveguide. This approach leads to a ~1dB insertion loss level up to moderately high light group indices (nG≈30) in wavelength ranges of 5-10nm. This work brings new opportunities to inject light into the slow modes of slot photonic crystal waveguides for on-chip communications using hybrid silicon photonics or sensing based on hollow core waveguides.

  4. Conventional and high intensity halogen light effects on water sorption and microhardness of orthodontic adhesives.

    Science.gov (United States)

    Uysal, Tancan; Basciftci, Faruk Ayhan; Sener, Yagmur; Botsali, Murat Selim; Demir, Abdullah

    2008-01-01

    To test the null hypothesis that when the equivalent total light energy is irradiated to three orthodontic adhesive resins, there is no difference between the microhardness and water sorption values regardless of the curing light sources. Samples were divided into six groups according to the combination of three orthodontic adhesives (Kurasper F, Light-Bond, Transbond XT) and two light intensities (quartz tungsten halogen [QTH] and high intensity quartz tungsten halogen [HQTH]). One half of each of the 40 samples of three adhesive pastes was polymerized for 20 seconds by a QTH light source, and the other half was polymerized for 10 seconds by a HQTH light source. Water sorption was determined and Vickers hardness was established with three measurements per sample at the top, center, and bottom. Statistical analysis was performed using two-way analysis of variance (ANOVA) with multiple comparisons (Tukey-HSD). Statistically significant differences were found among all adhesives for water sorption and hardness values cured with QTH and HQTH. The HQTH curing unit resulted in higher values than did the QTH. The highest water sorption values were observed for Kurasper F cured with HQTH and the lowest value was observed for Transbond XT cured with QTH. For microhardness Light-Bond cured with HQTH produced the highest values, and Transbond XT cured with QTH produced the lowest. When the equivalent total light energy is irradiated to three orthodontic adhesive resins, there are significant differences between the microhardness and water sorption values cured with the QTH and HQTH light source. The null hypothesis is rejected.

  5. Near-infrared light controlled photocatalytic activity of carbon quantum dots for highly selective oxidation reaction

    Science.gov (United States)

    Li, Haitao; Liu, Ruihua; Lian, Suoyuan; Liu, Yang; Huang, Hui; Kang, Zhenhui

    2013-03-01

    Selective oxidation of alcohols is a fundamental and significant transformation for the large-scale production of fine chemicals, UV and visible light driven photocatalytic systems for alcohol oxidation have been developed, however, the long wavelength near infrared (NIR) and infrared (IR) light have not yet fully utilized by the present photocatalytic systems. Herein, we reported carbon quantum dots (CQDs) can function as an effective near infrared (NIR) light driven photocatalyst for the selective oxidation of benzyl alcohol to benzaldehyde. Based on the NIR light driven photo-induced electron transfer property and its photocatalytic activity for H2O2 decomposition, this metal-free catalyst could realize the transformation from benzyl alcohol to benzaldehyde with high selectivity (100%) and conversion (92%) under NIR light irradiation. HO&z.rad; is the main active oxygen specie in benzyl alcohol selective oxidative reaction confirmed by terephthalic acid photoluminescence probing assay (TA-PL), selecting toluene as the substrate. Such metal-free photocatalytic system also selectively converts other alcohol substrates to their corresponding aldehydes with high conversion, demonstrating a potential application of accessing traditional alcohol oxidation chemistry.Selective oxidation of alcohols is a fundamental and significant transformation for the large-scale production of fine chemicals, UV and visible light driven photocatalytic systems for alcohol oxidation have been developed, however, the long wavelength near infrared (NIR) and infrared (IR) light have not yet fully utilized by the present photocatalytic systems. Herein, we reported carbon quantum dots (CQDs) can function as an effective near infrared (NIR) light driven photocatalyst for the selective oxidation of benzyl alcohol to benzaldehyde. Based on the NIR light driven photo-induced electron transfer property and its photocatalytic activity for H2O2 decomposition, this metal-free catalyst could realize

  6. Response of conifer species from three latitudinal populations to light spectra generated by light-emitting diodes and high-pressure sodium lamps

    Science.gov (United States)

    Kent G. Apostol; Kas Dumroese; Jeremy Pinto; Anthony S. Davis

    2015-01-01

    Light-emitting diode (LED) technology shows promise for supplementing photosynthetically active radiation (PAR) in forest nurseries because of the potential reduction in energy consumption and an ability to supply discrete wavelengths to optimize seedling growth. Our objective was to examine the effects of light spectra supplied by LED and traditional high-pressure...

  7. High efficiency light source using solid-state emitter and down-conversion material

    Science.gov (United States)

    Narendran, Nadarajah; Gu, Yimin; Freyssinier, Jean Paul

    2010-10-26

    A light emitting apparatus includes a source of light for emitting light; a down conversion material receiving the emitted light, and converting the emitted light into transmitted light and backward transmitted light; and an optic device configured to receive the backward transmitted light and transfer the backward transmitted light outside of the optic device. The source of light is a semiconductor light emitting diode, a laser diode (LD), or a resonant cavity light emitting diode (RCLED). The down conversion material includes one of phosphor or other material for absorbing light in one spectral region and emitting light in another spectral region. The optic device, or lens, includes light transmissive material.

  8. High-mast light poles anchor nut loosening in Alaska : an investigation of field monitoring and finite-element analysis.

    Science.gov (United States)

    2014-09-01

    High mast lighting poles (HMLPs) are tall, roadside structures effective for lighting large areas of highways and intersections. The Alaska Department of Transportation : and Public Facilities (AKDOT&PF) maintains 118 such poles in the greater Anchor...

  9. Effective market influence. An effect chain analysis of NUTEK`s high-frequency lighting campaign

    Energy Technology Data Exchange (ETDEWEB)

    Goeransson, C.; Faugert, S. [SIPU Utvaerdering, Stockholm (Sweden); Baeckman, B.; Arndt, J. [B2B AB, Stockholm (Sweden)

    1994-12-31

    This report is an evaluation of NUTEK`s `Better lighting and more energy-efficient high-frequency fluorescent tube luminaries` campaign. It is concerned with the ways in which NUTEK can influence the spread and use of high-frequency (HF) lighting devices. It also shows that NUTEK actually has affected (contributed to) development in the area. The report analyses and quantifies (as far as possible) how much NUTEK has influenced the various parties concerned in the sector, their attitudes and their actions. 14 figs, 5 tabs

  10. The effect of high correlated colour temperature office lighting on employee wellbeing and work performance

    Directory of Open Access Journals (Sweden)

    Tomkins Susannah C

    2007-01-01

    Full Text Available Abstract Background The effects of lighting on the human circadian system are well-established. The recent discovery of 'non-visual' retinal receptors has confirmed an anatomical basis for the non-image forming, biological effects of light and has stimulated interest in the use of light to enhance wellbeing in the corporate setting. Methods A prospective controlled intervention study was conducted within a shift-working call centre to investigate the effect of newly developed fluorescent light sources with a high correlated colour temperature (17000 K upon the wellbeing, functioning and work performance of employees. Five items of the SF-36 questionnaire and a modification of the Columbia Jet Lag scale, were used to evaluate employees on two different floors of the call centre between February and May 2005. Questionnaire completion occurred at baseline and after a three month intervention period, during which time one floor was exposed to new high correlated colour temperature lighting and the other remained exposed to usual office lighting. Two sided t-tests with Bonferroni correction for type I errors were used to compare the characteristics of the two groups at baseline and to evaluate changes in the intervention and control groups over the period of the study. Results Individuals in the intervention arm of the study showed a significant improvement in self-reported ability to concentrate at study end as compared to those within the control arm (p Conclusion High correlated colour temperature fluorescent lights could provide a useful intervention to improve wellbeing and productivity in the corporate setting, although further work is necessary in quantifying the magnitude of likely benefits.

  11. Acclimation responses to high light by Guazuma ulmifolia Lam. (Malvaceae) leaves at different stages of development.

    Science.gov (United States)

    Calzavara, A K; Rocha, J S; Lourenço, G; Sanada, K; Medri, C; Bianchini, E; Pimenta, J A; Stolf-Moreira, R; Oliveira, H C

    2017-09-01

    The re-composition of deforested environments requires the prior acclimation of seedlings to full sun in nurseries. Seedlings can overcome excess light either through the acclimation of pre-existing fully expanded leaves or through the development of new leaves that are acclimated to the new light environment. Here, we compared the acclimation capacity of mature (MatL, fully expanded at the time of transfer) and newly expanded (NewL, expanded after the light shift) leaves of Guazuma ulmifolia Lam. (Malvaceae) seedlings to high light. The seedlings were initially grown under shade and then transferred to full sunlight. MatL and NewL were used for chlorophyll fluorescence and gas exchange analyses, pigment extraction and morpho-anatomical measurements. After the transfer of seedlings to full sun, the MatL persisted and acclimated to some extent to the new light condition, since they underwent alterations in some morpho-physiological traits and maintained a functional electron transport chain and positive net photosynthesis rate. However, long-term exposure to high light led to chronic photoinhibition in MatL, which could be related to the limited plasticity of leaf morpho-anatomical attributes. However, the NewL showed a high capacity to use the absorbed energy in photochemistry and dissipate excess energy harmlessly, attributes that were favoured by the high structural plasticity exhibited by these leaves. Both the maintenance of mature, photosynthetically active leaves and the production of new leaves with a high capacity to cope with excess energy were important for acclimation of G. ulmifolia seedlings. © 2017 German Botanical Society and The Royal Botanical Society of the Netherlands.

  12. High efficiency, high modulation bandwidth (Ga,Al)As:Te,Zn light-emitting diodes with graded band gap

    Science.gov (United States)

    Leibenzeder, S.; Rühle, W.; Hoffmann, L.; Weyrich, C.

    1985-05-01

    A new (Ga,Al)As light-emitting diode (λmax =660-880 nm) is presented which has several advantages: simple processing, high external quantum efficiencies (up to 12%), and short decay times (down to 12 ns). The importance of photon recycling and reduced self-absorption in the graded band gap is demonstrated.

  13. Concept of coherence aperture and pathways toward white light high-resolution correlation imaging

    Science.gov (United States)

    Bouchal, P.; Bouchal, Z.

    2013-12-01

    Self-interference correlation imaging is a recently discovered method that takes advantage of holographic reconstruction when using a spatially incoherent light. Although the temporal coherence of light significantly influences the resolution of the method, it has not been studied either theoretically or experimentally. We present the first systematic study of the resolution in a broadband correlation imaging based on the concept of coherence-induced diffraction. We show that the physical limits of the resolution are reached in a non-dispersive experiment and their examination can be performed by the coherence aperture whose width depends on the coherence length of light and the optical path difference of interfering waves. As the main result, the optimal configuration of the non-dispersive experimental system is found in which the sub-diffraction image resolution previously demonstrated for monochromatic light can be retained even when the white light is used. Dispersion effects that prevent reaching the physical resolution limits are discussed and the dispersion sensitivity of the currently available experiments examined. The proposed concept of the coherence aperture is verified experimentally and its generalization to the concept of the dispersion-induced aperture suggested. As a challenge for future research, possible methods of dispersion elimination are outlined that allow the design of advanced optical systems enabling implementation of the high-resolution white light correlation imaging.

  14. A High Performance Photodetector Suitable for Visible Light and Near Infrared Applications

    Science.gov (United States)

    Lai, Kuang-Sheng; Huang, Ji-Chen; Hsu, Klaus Y.-J.

    2008-04-01

    In this work, the high performance phototransistor photodetector (PTPD) in commercial 0.35 µm SiGe bipolar junction transistor complementary metal oxide semiconductor (BiCMOS) process without altering any process step is demonstrated and analyzed. The device combines a surface photodetector (SPD) and a conventional SiGe heterojunction transistor (HBT). It is shown that the SPD enhances light absorption, especially for the blue light. With the proper bias configuration, the PTPD shows acceptable dark current and a bias voltage that can be as low as 0.3 V. The Emitter and SPD areas can be respectively designed to meet electrical and optical requirements without increasing the device capacitance. Besides, high responsivities of 5.69/9.47/7.11 A/W for 450/670/780 nm lights were achieved in the PTPD, which makes the device suitable for many applications.

  15. High-energy gamma-ray beams from Compton-backscattered laser light

    Energy Technology Data Exchange (ETDEWEB)

    Sandorfi, A.M.; LeVine, M.J.; Thorn, C.E.; Giordano, G.; Matone, G.

    1983-01-01

    Collisions of light photons with relativistic electrons have previously been used to produce polarized ..gamma..-ray beams with modest (-10%) resolution but relatively low intensity. In contrast, the LEGS project (Laser + Electron Gamma Source) at Brookhaven will produce a very high flux (>2 x 10/sup 7/ s/sup -1/) of background-free polarized ..gamma.. rays whose energy will be determined to a high accuracy (..delta..E = 2.3 MeV). Initially, 300(420)-MeV ..gamma.. rays will be produced by backscattering uv light from the new 2.5(3.0)-GeV X-ray storage ring of the National Synchrotron Light Source (NSLS). The LEGS facility will operate as one of many passive users of the NSLS. In a later stage of the project, a Free Electron Laser is expectred to extend the ..gamma..-ray energy up to 700 MeV.

  16. High-performance light-emitting diodes based on carbene-metal-amides

    Science.gov (United States)

    Di, Dawei; Romanov, Alexander S.; Yang, Le; Richter, Johannes M.; Rivett, Jasmine P. H.; Jones, Saul; Thomas, Tudor H.; Abdi Jalebi, Mojtaba; Friend, Richard H.; Linnolahti, Mikko; Bochmann, Manfred; Credgington, Dan

    2017-04-01

    Organic light-emitting diodes (OLEDs) promise highly efficient lighting and display technologies. We introduce a new class of linear donor-bridge-acceptor light-emitting molecules, which enable solution-processed OLEDs with near-100% internal quantum efficiency at high brightness. Key to this performance is their rapid and efficient utilization of triplet states. Using time-resolved spectroscopy, we establish that luminescence via triplets occurs within 350 nanoseconds at ambient temperature, after reverse intersystem crossing to singlets. We find that molecular geometries exist at which the singlet-triplet energy gap (exchange energy) is close to zero, so that rapid interconversion is possible. Calculations indicate that exchange energy is tuned by relative rotation of the donor and acceptor moieties about the bridge. Unlike other systems with low exchange energy, substantial oscillator strength is sustained at the singlet-triplet degeneracy point.

  17. Long-term failure rate of brackets bonded with plasma and high-intensity light-emitting diode curing lights:a clinical assessment.

    Science.gov (United States)

    Pandis, Nikolaos; Strigou, Sophia; Eliades, Theodore

    2007-07-01

    To comparatively assess the long-term failure rate of brackets bonded with a plasma or a high-intensity light-emitting diode (LED) curing light. Twenty-five patients with complete permanent dentitions with similar treatment planning and mechanotherapy were selected for the study. Brackets were bonded according to a split-mouth design with the 3M Ortholite Plasma or the high-power Satelec mini LED Ortho curing light. Irradiation with the two curing lights was performed for 9 seconds at an alternate quadrant sequence so that the bonded brackets cured with either light were equally distributed on the maxillary and mandibular right and left quadrants. First-time bracket failures were recorded for a mean period of 15 months (range 13-18 months) and the results were analyzed with the chi-square test and binary logistic regression. The failure rate for brackets was 2.8% for the plasma light and 6.7% for the LED light source. Although significantly more failures were found for the mandibular arch, no difference was identified in failure rate between anterior and posterior teeth. High-intensity LED curing lights present a 2.5 times higher failure rate relative to plasma lamps for nominally identical irradiation time. Mandibular teeth show almost 150% higher failure incidence compared with maxillary teeth. No effect from the arch side (right vs left) and location (anterior vs posterior) was identified in this study.

  18. Differential responses of seven contrasting species to high light using pigment and chlorophyll a fluorescence

    Directory of Open Access Journals (Sweden)

    Mittal S.

    2011-05-01

    Full Text Available High light intensity may induce severe photodamage to chloroplast and consequently cause decreases in the yield capacity of plants and destruction of pigments, causing an overall yellowing of the foliage. Thus, study related to light adaptation becomes necessary to understand adaptation processes in higher plants on the basis of which they are characterized as full sunlight or shade plants. Chlorophyll can be regarded as an intrinsic fluorescent probe of the photosynthetic system. The ecophysiological parameter related to plant performance and fitness i.e. in-situ chlorophyll fluorescence measurements were determined for different plant species in the medicinal plant garden of Banasthali University, Rajasthan. Miniaturized Pulse Amplitude Modulated Photosynthetic Yield Analyzers are primarily designed for measuring effective quantum yield (ΔF/Fm’ of photosystem II under momentary ambient light in the field. Photosynthetic yield measurements and light-response curves suggested a gradation of sun-adapted to shade-adapted behaviour of these plants in following order Withania somnifera> Catharanthus roseus> Datura stamonium> Vasica minora> Vasica adulta> Rauwolfia serpentina. As indicated by light response curves and pigment analysis, Datura stramonium, Withania somnifera and Catharanthus roseus competed well photosynthetically and are favoured while Rauwolfia serpentina, Vasica minora, Vasica adulta and Plumbago zeylanica were observed to be less competent photosynthetically. These light response curves and resultant cardinal points study gave insight into the ecophysiological characterization of the photosynthetic capacity of the plant and provides highly interesting parameters like electron transport rate, photo-inhibition, photosynthetically active photon flux density and yield on the basis of which light adaptability was screened for seven medicinally important plants.

  19. Highly conductive copper nano/microparticles ink via flash light sintering for printed electronics.

    Science.gov (United States)

    Joo, Sung-Jun; Hwang, Hyun-Jun; Kim, Hak-Sung

    2014-07-04

    In this study, the size effect of copper particles on the flash light sintering of copper (Cu) ink was investigated using Cu nanoparticles (20-50 nm diameter) and microparticles (2 μm diameter). Also, the mixed Cu nano-/micro-inks were fabricated, and the synergetic effects between the Cu nano-ink and micro-ink on flash light sintering were assessed. The ratio of nanoparticles to microparticles in Cu ink and the several flash light irradiation conditions (irradiation energy density, pulse number, on-time, and off-time) were optimized to obtain high conductivity of Cu films. In order to precisely monitor the milliseconds-long flash light sintering process, in situ monitoring of electrical resistance and temperature changes of Cu films was conducted during the flash light irradiation using a real-time Wheatstone bridge electrical circuit, thermocouple-based circuit, and a high-rate data acquisition system. Also, several microscopic and spectroscopic characterization techniques such as scanning electron microscopy, x-ray diffraction, x-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy were used to characterize the flash light sintered Cu nano-/micro-films. In addition, the sheet resistance of Cu film was measured using a four-point probe method. This work revealed that the optimal ratio of nanoparticles to microparticles is 50:50 wt%, and the optimally fabricated and flash light sintered Cu nano-/micro-ink films have the lowest resistivity (80 μΩ cm) among nano-ink, micro-ink, or nano-micro mixed films.

  20. Oxygen deficient ZnO 1-x nanosheets with high visible light photocatalytic activity.

    Science.gov (United States)

    Guo, Hong-Li; Zhu, Qing; Wu, Xi-Lin; Jiang, Yi-Fan; Xie, Xiao; Xu, An-Wu

    2015-04-28

    Zinc oxide is one of the most important wide-band-gap (3.2 eV) materials with versatile properties, however, it can not be excited by visible light. In this work, we have developed an exquisite and simple way to prepare oxygen-deficient ZnO 1-x nanosheets with a gray-colored appearance and excellent visible light photocatalytic activity. Detailed analysis based on UV-Vis absorption spectra, X-band electron paramagnetic resonance (EPR) spectra, and photoluminescence (PL) spectra confirms the existence of oxygen vacancies in ZnO 1-x. The incorporation of oxygen defects could effectively extend the light absorption of ZnO 1-x into the visible-light region due to the fact that the energy of the localized state is located in the forbidden gap. Thus, our obtained ZnO 1-x shows a higher photodegradation of methyl orange (MO) compared to defect-free ZnO under visible light illumination. Additionally, the high content of ˙OH radicals with a strong photo-oxidation capability over the ZnO 1-x nanosheets significantly contributes to the improvement in the photocatalytic performance. Our oxygen deficient ZnO 1-x sample shows a very high photocatalytic activity for the degradation of MO even after 5 cycles without any obvious decline. The results demonstrate that defect engineering is a powerful tool to enhance the optoelectronic and photocatalytic performances of nanomaterials.

  1. A comparison of light-coupling into high and low index nanostructured photovoltaic thin films

    Directory of Open Access Journals (Sweden)

    T. Pfadler

    2015-06-01

    Full Text Available Periodically structured electrodes are typically introduced to thin-film photovoltaics for the purpose of light management. Highly effective light-trapping and optimal in-coupling of light is crucial to enhance the overall device performance in such thin-film systems. Here, wavelength-scale structures are transferred via direct laser interference patterning to electron-selective TiO2 electrodes. Two representative thin-film solar cell architectures are deposited on top: an organic solar cell featuring blended P3HT:PCBM as active material, and a hybrid solar cell with Sb2S3 as inorganic active material. A direct correlation in the asymmetry in total absorption enhancement and in structure-induced light in-coupling is spectroscopically observed for the two systems. The structuring is shown to be beneficial for the total absorption enhancement if a high n active material is deposited on TiO2, but detrimental for a low n material. The refractive indices of the employed materials are determined via spectroscopic ellipsometry. The study outlines that the macroscopic Fresnel equations can be used to investigate the spectroscopically observed asymmetry in light in-coupling at the nanostructured TiO2 active material interfaces by visualizing the difference in reflectivity caused by the asymmetry in refractive indices.

  2. Achieving Energy Savings with Highly-Controlled Lighting in an Open-Plan Office

    Energy Technology Data Exchange (ETDEWEB)

    Rubinstein, Francis; Enscoe, Abby

    2010-04-19

    An installation in a Federal building tested the effectiveness of a highly-controlled, workstation-specific lighting retrofit. The study took place in an open-office area with 86 cubicles and low levels of daylight. Each cubicle was illuminated by a direct/indirectpendant luminaire with three 32 watt lamps, two dimmable DALI ballasts, and an occupancy sensor. A centralized control system programmed all three lamps to turn on and off according to occupancy on a workstation-by-workstation basis. Field measurements taken over the course of several monthsdemonstrated 40% lighting energy savings compared to a baseline without advanced controls that conforms to GSA's current retrofit standard. A photometric analysis found that the installation provided higher desktop light levels than the baseline, while an occupant survey found that occupants in general preferred the lighting system to thebaseline.Simple payback is fairly high; projects that can achieve lower installation costs and/or higher energy savings and those in which greenhouse gas reduction and occupant satisfaction are significant priorities provide the ideal setting for workstation-specific lighting retrofits.

  3. Prospects for high-gain, high yield NIF targets driven by 2ω (green) light

    Science.gov (United States)

    Suter, L. J.; Glenzer, S.; Haan, S.; Hammel, B.; Manes, K.; Meezan, N.; Moody, J.; Spaeth, M.; Oades, K.; Stevenson, M.

    2016-10-01

    For several years we have been exploring the possibility of using green (2w) light for indirect drive ignition on NIF. The rationale for this work is the possibility of extracting significantly more energy from NIF in green light, as compared to blue (3w) light, and driving far more energetic capsules than we originally envisioned when we started planning NIF in the early 1990's. This paper attempts to provide a comprehensive picture of the progress we have made exploring 2w for NIF ignition. First we describe the potential operating regime for NIF at 2w and how that can translate into a very large "design space" for exploring ignition target designs. We then present the results of 2w ignition target design studies indicating that we can achieving adequate drive and symmetry with 2w and showing how we might capitalize on the large amount of energy available by electing to trade-off coupling efficiency for, say, better symmetry or plasma conditions. These simulations also define plasma conditions for ignition-relevant 2w laser-plasma interaction experiments that have been recently performed. We summarize the results of these experiments which indicate that 2w LPI is not very different from 3w's. Finally, we show how recent experimental findings on mitigating 2w laser plasma interactions through reduced intensity and/or judicious choice of plasma composition can be incorporated into ignition target designs.

  4. Very High Frequency Resonant DC/DC Converters for LED Lighting

    DEFF Research Database (Denmark)

    Madsen, Mickey Pierre; Knott, Arnold; Andersen, Michael A. E.

    2013-01-01

    This paper presents a very high frequency DC/DC converter for LED lighting. Several resonant topologies are compared and their usability discussed. At the end the resonant SEPIC converter is chosen based on the achievable power density and total bill of material. Simulations of a 51 MHz converter...

  5. The light-hyperresponsive high pigment-2dg mutation of tomato: alterations in the fruit metabolome

    NARCIS (Netherlands)

    Bino, R.J.; Vos, de C.H.; Lieberman, M.; Hall, R.D.; Bovy, A.G.; Jonker, H.H.; Tikunov, Y.M.; Lommen, A.; Moco, S.I.A.; Levin, I.

    2005-01-01

    Overall metabolic modifications between fruit of light-hyperresponsive high-pigment (hp) tomato (Lycopersicon esculentum) mutant plants and isogenic nonmutant (wt) control plants were compared. Targeted metabolite analyses, as well as large-scale nontargeted mass spectrometry (MS)-based metabolite

  6. Selected List of Low Energy Beam Transport Facilities for Light-Ion, High-Intensity Accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Prost, L. R. [Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States)

    2016-02-17

    This paper presents a list of Low Energy Beam Transport (LEBT) facilities for light-ion, high-intensity accelerators. It was put together to facilitate comparisons with the PXIE LEBT design choices. A short discussion regarding the importance of the beam perveance in the choice of the transport scheme follows.

  7. High-throughput Transcriptome Sequencing Reveals the Role of Anthocyanin Metabolism in Begonia semperflorens Under High Light Stress.

    Science.gov (United States)

    Wang, Jiawan; Guo, Meili; Li, Yonghua; Wu, Ronghua; Zhang, Kaiming

    2017-07-26

    Begonia semperflorens is an ornamental perennial herb. The leaves of B. semperflorens turn red under increased light, which increases the ornamental value of the plant. The color of the leaves is determined by anthocyanin metabolism. In B. semperflorens leaves, anthocyanin metabolism is sensitive to external environmental conditions such as temperature, light and hormone levels. To explore this process in detail and to assess gene expression under high light stress, transcriptome analysis was performed by RNA sequencing using the sequencing-by-synthesis method. A total of 83 699 unigenes were isolated, and 51 754 unigenes were annotated using the NR, Swiss-Prot, KEGG, COG, KOG, GO and Pfam databases. Furthermore, many of the differentially expressed genes were related to factors associated with anthocyanin metabolism, which influences the expression of leaf color. © 2017 The American Society of Photobiology.

  8. Broadband Light Absorption and Efficient Charge Separation Using a Light Scattering Layer with Mixed Cavities for High-Performance Perovskite Photovoltaic Cells with Stability.

    Science.gov (United States)

    Moon, Byeong Cheul; Park, Jung Hyo; Lee, Dong Ki; Tsvetkov, Nikolai; Ock, Ilwoo; Choi, Kyung Min; Kang, Jeung Ku

    2017-08-01

    CH3 NH3 PbI3 is one of the promising light sensitizers for perovskite photovoltaic cells, but a thick layer is required to enhance light absorption in the long-wavelength regime ranging from PbI2 absorption edge (500 nm) to its optical band-gap edge (780 nm) in visible light. Meanwhile, the thick perovskite layer suppresses visible-light absorption in the short wavelengths below 500 nm and charge extraction capability of electron-hole pairs produced upon light absorption. Herein, we find that a new light scattering layer with the mixed cavities of sizes in 100 and 200 nm between transparent fluorine-doped tin oxide and mesoporous titanium dioxide electron transport layer enables full absorption of short-wavelength photons (λ cell with a light scattering layer of mixed cavities is stabilized due to suppressed charge accumulation. Consequently, this work provides a new route to realize broadband light harvesting of visible light for high-performance perovskite photovoltaic cells. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Effects of various LED light wavelengths and light intensity supply strategies on synthetic high-strength wastewater purification by Chlorella vulgaris.

    Science.gov (United States)

    Yan, Cheng; Zhao, Yongjun; Zheng, Zheng; Luo, Xingzhang

    2013-09-01

    Chemical fertilizer agricultural wastewater is a typical high-strength wastewater that has dramatically triggered numerous environmental problems in China. The Chlorella vulgaris microalgae biological wastewater treatment system used in this study can effectively decontaminate the high-strength carbon and nitrogen wastewater under an optimum light wavelength and light intensity supply strategy. The descending order of both the dry weight for C. vulgaris reproduction and wastewater nutrient removal efficiency is red > white > yellow > purple > blue > green, which indicates that red light is the optimum light wavelength. Furthermore, rather than constant light, optimal light intensity is used for the incremental light intensity strategy. The phases for the optimal light intensity supply strategy are as follows: Phase 1 from 0 to 48 h at 800 μmol m(-2) s(-1); Phase 2 from 48 to 96 h at 1,200 μmol m(-2) s(-1); and Phase 3 from 96 to 144 h at 1,600 μmol m(-2) s(-1). Additionally, the optimal cultivation time is 144 h.

  10. Demonstration of high-speed multi-user multi-carrier CDMA visible light communication

    Science.gov (United States)

    Yang, Chao; Wang, Yuanquan; Wang, Yiguang; Huang, Xingxing; Chi, Nan

    2015-02-01

    We experimentally demonstrated a high-speed multi-user multi-carrier code-division multiple access (MC-CDMA) visible light communication (VLC) system. By employing a commercially available red light emitting diode (LED) and an avalanche photo diode (APD), we achieved a 16-user VLC system enabled by MC-CDMA, pre- and post-equalization, with an overall bit rate of 750 Mb/s over 1.5 m free-space transmission. The measured bit error ratio (BER) of each user is below the 7% pre-forward-error-correction (pre-FEC) threshold of 3.8×10-3.

  11. High efficiency and brightness fluorescent organic light emitting diode by triplet-triplet fusion

    Science.gov (United States)

    Forrest, Stephen; Zhang, Yifan

    2015-02-10

    A first device is provided. The first device further comprises an organic light emitting device. The organic light emitting device further comprises an anode, a cathode, and an emissive layer disposed between the anode and the cathode. The emissive layer may include an organic host compound and at least one organic emitting compound capable of fluorescent emission at room temperature. Various configurations are described for providing a range of current densities in which T-T fusion dominates over S-T annihilation, leading to very high efficiency fluorescent OLEDs.

  12. Differences in photosynthetic responses of NADP-ME type C4 species to high light.

    Science.gov (United States)

    Romanowska, Elżbieta; Buczyńska, Alicja; Wasilewska, Wioleta; Krupnik, Tomasz; Drożak, Anna; Rogowski, Paweł; Parys, Eugeniusz; Zienkiewicz, Maksymilian

    2017-03-01

    Three species chosen as representatives of NADP-ME C4 subtype exhibit different sensitivity toward photoinhibition, and great photochemical differences were found to exist between the species. These characteristics might be due to the imbalance in the excitation energy between the photosystems present in M and BS cells, and also due to that between species caused by the penetration of light inside the leaves. Such regulation in the distribution of light intensity between M and BS cells shows that co-operation between both the metabolic systems determines effective photosynthesis and reduces the harmful effects of high light on the degradation of PSII through the production of reactive oxygen species (ROS). We have investigated several physiological parameters of NADP-ME-type C4 species (e.g., Zea mays, Echinochloa crus-galli, and Digitaria sanguinalis) grown under moderate light intensity (200 µmol photons m-2 s-1) and, subsequently, exposed to excess light intensity (HL, 1600 µmol photons m-2 s-1). Our main interest was to understand why these species, grown under identical conditions, differ in their responses toward high light, and what is the physiological significance of these differences. Among the investigated species, Echinochloa crus-galli is best adapted to HL treatment. High resistance of the photosynthetic apparatus of E. crus-galli to HL was accompanied by an elevated level of phosphorylation of PSII proteins, and higher values of photochemical quenching, ATP/ADP ratio, activity of PSI and PSII complexes, as well as integrity of the thylakoid membranes. It was also shown that the non-radiative dissipation of energy in the studied plants was not dependent on carotenoid contents and, thus, other photoprotective mechanisms might have been engaged under HL stress conditions. The activity of the enzymes superoxide dismutase and ascorbate peroxidase as well as the content of malondialdehyde and H2O2 suggests that antioxidant defense is not responsible

  13. Inhibition of enteric pathogens and surrogates using integrated, high intensity 405nm led light on the surface of almonds

    Science.gov (United States)

    The disinfecting properties of 405 nm light were investigated against Escherichia coli O157:H7, Salmonella, and their non-pathogenic surrogate bacteria on the surface of almonds. High intensity monochromatic blue light (MBL) was generated from an array of narrow-band 405 nm light-emitting diodes (LE...

  14. A facile and high sensitive micro fluorimeter based on light emitting diode and photodiode.

    Science.gov (United States)

    Geng, Xuhui; Gao, Yan; Feng, Chunbo; Guan, Yafeng

    2017-12-01

    A facile and high sensitive micro fluorimeter was developed and evaluated. It employed light emitting diode (LED) as light source, cuvette as detection cell, and photodiode (PD) as optoelectronic detector. Optical and electronic parameters were optimized and demonstrated. A high power LED was chosen, which could irradiate the inner area of the cuvette completely at the same time with divergence angle as small as possible. The optimum LED brought 2.5 times signal-to-noise ratio (SNR) enhancement. Using reflector at the opposite direction of excitation light path doubled SNR. The amplifier circuit of PD was deeply investigated to achieve high sensitivity, low noise, and good stability. The limit of detection (LOD) of fluorescein isothiocyanate (FITC) and chlorophyll at SNR = 3 were 10pM ~ 0.004 ppb and 0.05 ppb, respectively. Basing on the principle structure, a portable fluorimeter for fungimycin detection was developed using a low power UV LED as light source. The LOD for aflatoxin B1 was 0.1 ppb. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. The high frequency characteristics of laser reflection and visible light during solid state disk laser welding

    Science.gov (United States)

    Gao, Xiangdong; You, Deyong; Katayama, Seiji

    2015-07-01

    Optical properties are related to weld quality during laser welding. Visible light radiation generated from optical-induced plasma and laser reflection is considered a key element reflecting weld quality. An in-depth analysis of the high-frequency component of optical signals is conducted. A combination of a photoelectric sensor and an optical filter helped to obtain visible light reflection and laser reflection in the welding process. Two groups of optical signals were sampled at a high sampling rate (250 kHz) using an oscilloscope. Frequencies in the ranges 1-10 kHz and 10-125 kHz were investigated respectively. Experimental results showed that there was an obvious correlation between the high-frequency signal and the laser power, while the high-frequency signal was not sensitive to changes in welding speed. In particular, when the defocus position was changed, only a high frequency of the visible light signal was observed, while the high frequency of the laser reflection signal remained unchanged. The basic correlation between optical features and welding status during the laser welding process is specified, which helps to provide a new research focus for investigating the stability of welding status.

  16. Wide-angle and high-efficiency achromatic metasurfaces for visible light

    CERN Document Server

    Deng, Zi-Lan; Wang, Guo Ping

    2016-01-01

    Recently, an achromatic metasurface was successfully demonstrated to deflect light of multiple wavelengths in the same direction and it was further applied to the design of planar lenses without chromatic aberrations [Science, 347, 1342(2015)]. However, such metasurface can only work for normal incidence and exhibit low conversion efficiency. Here, we present an ultrawide-angle and high-efficiency metasurface without chromatic aberration for wavefront shaping in visible range. The metasurface is constructed by multiple metallic nano-groove gratings, which support enhanced diffractions for an ultrawide incident angle range from 10o to 80o due to the excitations of localized gap plasmon modes at different resonance wavelengths. Incident light at these resonance wavelengths can be efficiently diffracted into the same direction with complete suppression of the specular reflection. This approach is applied to the design of an achromatic flat lens for focusing light of different wavelengths into the same position. ...

  17. Thermally stable conformal encapsulation material for high-power ultraviolet light-emitting diodes

    Science.gov (United States)

    Huang, Shun-Yuan; Wang, Jau-Sheng

    2017-07-01

    A conformal encapsulation material for use in high-power, thermally stable ultraviolet (UV) light-emitting diodes was successfully developed. For silicone, thermal degradation started at ˜200°C, and the transmittance was 85.5% at 365 nm. The transmittance decreased by 55% after thermal aging at 250°C for 72 h and it decreased further by 2.5%, even at room temperature, under continuous exposure to UV light at 365 nm for 72 h. By contrast, for the sol-gel material, thermal degradation started at ˜300°C, and the transmittance was 90% at 365 nm. The transmittance decreased negligibly after thermal aging at 250°C for 72 h and it did not decrease further even at 75°C under continuous exposure to UV light at 365 nm for 72 h.

  18. Investigating the Mobility of Light Autonomous Tracked Vehicles using a High Performance Computing Simulation Capability

    Science.gov (United States)

    Negrut, Dan; Mazhar, Hammad; Melanz, Daniel; Lamb, David; Jayakumar, Paramsothy; Letherwood, Michael; Jain, Abhinandan; Quadrelli, Marco

    2012-01-01

    This paper is concerned with the physics-based simulation of light tracked vehicles operating on rough deformable terrain. The focus is on small autonomous vehicles, which weigh less than 100 lb and move on deformable and rough terrain that is feature rich and no longer representable using a continuum approach. A scenario of interest is, for instance, the simulation of a reconnaissance mission for a high mobility lightweight robot where objects such as a boulder or a ditch that could otherwise be considered small for a truck or tank, become major obstacles that can impede the mobility of the light autonomous vehicle and negatively impact the success of its mission. Analyzing and gauging the mobility and performance of these light vehicles is accomplished through a modeling and simulation capability called Chrono::Engine. Chrono::Engine relies on parallel execution on Graphics Processing Unit (GPU) cards.

  19. High peak power green light generation by frequency doubling of a superluminescent pulse amplifier system

    Science.gov (United States)

    Hao, He; Zhang, Haitao; He, Linlu; Gao, Gan; Gong, Mali

    2017-08-01

    We present an approach for green laser-light generation based on a fiber superluminescent pulse amplification system and frequency doubling to 552 nm with a periodically poled lithium niobate (PPLN) crystal. The SPA system used in the experiment is capable of yielding 6-nm-bandwidth, 10 ns pulsees. The 10-mm-long PPLN with 6.95 μm period and 0.5 mm thick generated high-power green light with single pulse energy up to 5.49 μJ when hte broadband input pulse coherence characteristics of the superluminescent pulse amplifier and the frequency doubling. This generated green light has proved to have low speckle noise and low photon degeneracy.

  20. High Incidence of Breast Cancer in Light-Polluted Areas with Spatial Effects in Korea.

    Science.gov (United States)

    Kim, Yun Jeong; Park, Man Sik; Lee, Eunil; Choi, Jae Wook

    2016-01-01

    We have reported a high prevalence of breast cancer in light-polluted areas in Korea. However, it is necessary to analyze the spatial effects of light polluted areas on breast cancer because light pollution levels are correlated with region proximity to central urbanized areas in studied cities. In this study, we applied a spatial regression method (an intrinsic conditional autoregressive [iCAR] model) to analyze the relationship between the incidence of breast cancer and artificial light at night (ALAN) levels in 25 regions including central city, urbanized, and rural areas. By Poisson regression analysis, there was a significant correlation between ALAN, alcohol consumption rates, and the incidence of breast cancer. We also found significant spatial effects between ALAN and the incidence of breast cancer, with an increase in the deviance information criterion (DIC) from 374.3 to 348.6 and an increase in R2 from 0.574 to 0.667. Therefore, spatial analysis (an iCAR model) is more appropriate for assessing ALAN effects on breast cancer. To our knowledge, this study is the first to show spatial effects of light pollution on breast cancer, despite the limitations of an ecological study. We suggest that a decrease in ALAN could reduce breast cancer more than expected because of spatial effects.

  1. Approach to Low-Cost High-Efficiency OLED Lighting. Building Technologies Solid State Lighting (SSL) Program Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Pei, Qibing [Univ. of California, Los Angeles, CA (United States). Dept. of Materials Science and Engineering

    2017-10-06

    This project developed an integrated substrate which organic light emitting diode (OLED) panel developers could employ the integrated substrate to fabricate OLED devices with performance and projected cost meeting the MYPP targets of the Solid State Lighting Program of the Department of Energy. The project optimized the composition and processing conditions of the integrated substrate for OLED light extraction efficiency and overall performance. The process was further developed for scale up to a low-cost process and fabrication of prototype samples. The encapsulation of flexible OLEDs based on this integrated substrate was also investigated using commercial flexible barrier films.

  2. Facile synthesis of cobalt-doped zinc oxide thin films for highly efficient visible light photocatalysts

    Energy Technology Data Exchange (ETDEWEB)

    Altintas Yildirim, Ozlem, E-mail: ozlemaltintas@gmail.com [Department of Metallurgical and Materials Engineering, Selcuk University, Konya (Turkey); Arslan, Hanife; Sönmezoğlu, Savaş [Department of Metallurgical and Materials Engineering, Karamanoglu Mehmetbey University, Karaman (Turkey); Nanotechnology R& D Laboratory, Karamanoglu Mehmetbey University, Karaman (Turkey)

    2016-12-30

    Highlights: • Photocatalytically active Co-ZnO thin film was obtained by sol-gel method. • Co{sup 2+} doping narrowed the band gap of pure ZnO to an extent of 3.18 eV. • Co-ZnO was effective in MB degradation under visible light. • Optimum dopant content to show high performance was 3 at.%. - Abstract: Cobalt-doped zinc oxide (Co:ZnO) thin films with dopant contents ranging from 0 to 5 at.% were prepared using the sol–gel method, and their structural, morphological, optical, and photocatalytic properties were characterized. The effect of the dopant content on the photocatalytic properties of the films was investigated by examining the degradation behavior of methylene blue (MB) under visible light irradiation, and a detailed investigation of their photocatalytic activities was performed by determining the apparent quantum yields (AQYs). Co{sup 2+} ions were observed to be substitutionally incorporated into Zn{sup 2+} sites in the ZnO crystal, leading to lattice parameter constriction and band gap narrowing due to the photoinduced carriers produced under the visible light irradiation. Thus, the light absorption range of the Co:ZnO films was improved compared with that of the undoped ZnO film, and the Co:ZnO films exhibited highly efficient photocatalytic activity (∼92% decomposition of MB after 60-min visible light irradiation for the 3 at.% Co:ZnO film). The AQYs of the Co:ZnO films were greatly enhanced under visible light irradiation compared with that of the undoped ZnO thin film, demonstrating the effect of the Co doping level on the photocatalytic activity of the films.

  3. Compact RGBY light sources with high luminance for laser display applications

    Science.gov (United States)

    Paschke, Katrin; Blume, Gunnar; Werner, Nils; Müller, André; Sumpf, Bernd; Pohl, Johannes; Feise, David; Ressel, Peter; Sahm, Alexander; Bege, Roland; Hofmann, Julian; Jedrzejczyk, Daniel; Tränkle, Günther

    2017-10-01

    Watt-class visible laser light with a high luminance can be created with high-power GaAs-based lasers either directly in the red spectral region or using single-pass second harmonic generation (SHG) for the colors in the blue-yellow spectral region. The concepts and results of red- and near infrared-emitting distributed Bragg reflector tapered lasers and master oscillator power amplifier systems as well as their application for SHG bench-top experiments and miniaturized modules are presented. Examples of these high-luminance light sources aiming at different applications such as flying spot display or holographic 3D cinema are discussed in more detail. The semiconductor material allows an easy adaptation of the wavelength allowing techniques such as six-primary color 3D projection or color space enhancement by adding a fourth yellow color.

  4. European research activities within the project: High Performance Light Water Reactor phase 2 (HPLWR phase 2)

    Energy Technology Data Exchange (ETDEWEB)

    Starflinger, J.; Schulenberg, T. [Forschungszentrum Karlsruhe GmbH, Institute for Nuclear and Energy Technologies, Karlsruhe (Germany); Marsault, P. [CEA Cadarache (DER/SESI), 13 - Saint Paul lez Durance (France). Dept. d' Etudes des Reacteurs; Bittermann, D. [AREVA NP, NEPR-G, Erlangen (Germany); Maraczy, C. [AEKI-KFKI, Budapest (Hungary); Laurien, E. [Stuttgart Univ. IKE (Germany); Lycklama, J.A. [NRG Petten, NL (Netherlands); Anglart, H. [KTH Energy Technology, Stockholm (Sweden); Aksan, N. [Paul Scherrer Institut CH, Villigen PSI (Switzerland); Ruzickova, M. [UJV Rez plc, Husinec-Rez c.p. (Czech Republic); Heikinheimo, L. [VTT, FIN (Finland)

    2007-07-01

    The High Performance Light Water Reactor (HPLWR) is a Light Water Reactor (LWR) operating at supercritical pressure (25 MPa). It belongs to the six reactors currently being investigated under the framework of the Generation IV International Forum. The most visible advantage of the HPLWR shall be the low construction costs in the order of 1000 Euro/kWe, because of size reduction of components and buildings compared to current Light Water Reactors, and the low electricity production costs which are targeted at 3-4 cents/kWh. In Europe, investigations on the HPLWR have been integrated into a joint research project, called High Performance Light Water Reactor Phase 2 (HPLWR Phase 2), which is co-funded by the European Commission. Within 42 months, ten partners from eight European countries working on critical scientific issues shall show the feasibility of the HPLWR concept. This paper reports on 5 points relevant for HPLWR: 1) design and integration, 2) core design, 3) safety, 4) materials, and 5) heat transfer. The final goal is to assess the future potential of this reactor in the electricity market.

  5. Chlorine-functionalized carbon dots for highly efficient photodegradation of pollutants under visible-light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Shengliang, E-mail: hsliang@yeah.net [School of Material Science and Engineering, North University of China, Taiyuan 030051 (China); Ding, Yanli [School of Material Science and Engineering, North University of China, Taiyuan 030051 (China); Chang, Qing, E-mail: changneu@gmail.com [School of Material Science and Engineering, North University of China, Taiyuan 030051 (China); Yang, Jinlong [State Key Laboratory of New Ceramics and Fine Processing, Tsinghua University, Beijing 100084 (China); Lin, Kui, E-mail: linkui@tju.edu.cn [Analytical Instrumentation Center, Tianjin University, Tianjin 300072 (China)

    2015-11-15

    Graphical abstract: Chlorine-functionalized carbon dots (Cl-CDs) were synthesized through the substitution reaction. Cl-CDs show highly photocatalytic activity under visible-light irradiation, and can quickly degrade phthalocyanine with the thermal and chemical stability. This work suggests that surface engineering of carbon dots with heteroatoms can be used to enhance their photochemical properties. - Highlights: • Chlorine-functionalized carbon dots (Cl-CDs) were synthesized by substitution reaction. • Cl-CDs show highly photocatalytic activity under visible-light irradiation. • The thermally and chemically stable phthalocyanine is even photodegraded by Cl-CDs. - Abstract: Chlorine-functionalized carbon dots (Cl-CDs) were prepared by the substitution reaction between Cl radicals into thionyl chloride molecules and carbon dots with containing OH/COOH groups at their surface (O-CDs). The obtained Cl-CDs with a size of 2–5 nm contain 2–3% Cl atoms and emit blue light. Compared with amine-functionalzed carbon dots (N-CDs) and O-CDs, Cl-CDs exhibit much higher photocatalytic activity under visible-light irradiation. The thermally and chemically stable phthalocyanine can be even degraded quickly through Cl-CDs. This work suggests that surface engineering of carbon dots with heteroatoms can be used to enhance their photochemical properties.

  6. High-throughput estimation of incident light, light interception and radiation-use efficiency of thousands of plants in a phenotyping platform.

    Science.gov (United States)

    Cabrera-Bosquet, Llorenç; Fournier, Christian; Brichet, Nicolas; Welcker, Claude; Suard, Benoît; Tardieu, François

    2016-10-01

    Light interception and radiation-use efficiency (RUE) are essential components of plant performance. Their genetic dissections require novel high-throughput phenotyping methods. We have developed a suite of methods to evaluate the spatial distribution of incident light, as experienced by hundreds of plants in a glasshouse, by simulating sunbeam trajectories through glasshouse structures every day of the year; the amount of light intercepted by maize (Zea mays) plants via a functional-structural model using three-dimensional (3D) reconstructions of each plant placed in a virtual scene reproducing the canopy in the glasshouse; and RUE, as the ratio of plant biomass to intercepted light. The spatial variation of direct and diffuse incident light in the glasshouse (up to 24%) was correctly predicted at the single-plant scale. Light interception largely varied between maize lines that differed in leaf angles (nearly stable between experiments) and area (highly variable between experiments). Estimated RUEs varied between maize lines, but were similar in two experiments with contrasting incident light. They closely correlated with measured gas exchanges. The methods proposed here identified reproducible traits that might be used in further field studies, thereby opening up the way for large-scale genetic analyses of the components of plant performance. © 2016 INRA New Phytologist © 2016 New Phytologist Trust.

  7. Low Efficiency Upconversion Nanoparticles for High-Resolution Coalignment of Near-Infrared and Visible Light Paths on a Light Microscope.

    Science.gov (United States)

    Sundaramoorthy, Sriramkumar; Garcia Badaracco, Adrian; Hirsch, Sophia M; Park, Jun Hong; Davies, Tim; Dumont, Julien; Shirasu-Hiza, Mimi; Kummel, Andrew C; Canman, Julie C

    2017-03-08

    The combination of near-infrared (NIR) and visible wavelengths in light microscopy for biological studies is increasingly common. For example, many fields of biology are developing the use of NIR for optogenetics, in which an NIR laser induces a change in gene expression and/or protein function. One major technical barrier in working with both NIR and visible light on an optical microscope is obtaining their precise coalignment at the imaging plane position. Photon upconverting particles (UCPs) can bridge this gap as they are excited by NIR light but emit in the visible range via an anti-Stokes luminescence mechanism. Here, two different UCPs have been identified, high-efficiency micro540-UCPs and lower efficiency nano545-UCPs, that respond to NIR light and emit visible light with high photostability even at very high NIR power densities (>25 000 Suns). Both of these UCPs can be rapidly and reversibly excited by visible and NIR light and emit light at visible wavelengths detectable with standard emission settings used for Green Fluorescent Protein (GFP), a commonly used genetically encoded fluorophore. However, the high efficiency micro540-UCPs were suboptimal for NIR and visible light coalignment, due to their larger size and spatial broadening from particle-to-particle energy transfer consistent with a long-lived excited state and saturated power dependence. In contrast, the lower efficiency nano-UCPs were superior for precise coalignment of the NIR beam with the visible light path (∼2 μm versus ∼8 μm beam broadening, respectively) consistent with limited particle-to-particle energy transfer, superlinear power dependence for emission, and much smaller particle size. Furthermore, the nano-UCPs were superior to a traditional two-camera method for NIR and visible light path alignment in an in vivo Infrared-Laser-Evoked Gene Operator (IR-LEGO) optogenetics assay in the budding yeast Saccharomyces cerevisiae. In summary, nano-UCPs are powerful new tools for

  8. Highly Efficient Light-Emitting Diodes of Colloidal Metal-Halide Perovskite Nanocrystals beyond Quantum Size.

    Science.gov (United States)

    Kim, Young-Hoon; Wolf, Christoph; Kim, Young-Tae; Cho, Himchan; Kwon, Woosung; Do, Sungan; Sadhanala, Aditya; Park, Chan Gyung; Rhee, Shi-Woo; Im, Sang Hyuk; Friend, Richard H; Lee, Tae-Woo

    2017-07-25

    Colloidal metal-halide perovskite quantum dots (QDs) with a dimension less than the exciton Bohr diameter DB (quantum size regime) emerged as promising light emitters due to their spectrally narrow light, facile color tuning, and high photoluminescence quantum efficiency (PLQE). However, their size-sensitive emission wavelength and color purity and low electroluminescence efficiency are still challenging aspects. Here, we demonstrate highly efficient light-emitting diodes (LEDs) based on the colloidal perovskite nanocrystals (NCs) in a dimension > DB (regime beyond quantum size) by using a multifunctional buffer hole injection layer (Buf-HIL). The perovskite NCs with a dimension greater than DB show a size-irrespective high color purity and PLQE by managing the recombination of excitons occurring at surface traps and inside the NCs. The Buf-HIL composed of poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT:PSS) and perfluorinated ionomer induces uniform perovskite particle films with complete film coverage and prevents exciton quenching at the PEDOT:PSS/perovskite particle film interface. With these strategies, we achieved a very high PLQE (∼60.5%) in compact perovskite particle films without any complex post-treatments and multilayers and a high current efficiency of 15.5 cd/A in the LEDs of colloidal perovskite NCs, even in a simplified structure, which is the highest efficiency to date in green LEDs that use colloidal organic-inorganic metal-halide perovskite nanoparticles including perovskite QDs and NCs. These results can help to guide development of various light-emitting optoelectronic applications based on perovskite NCs.

  9. High-performance flexible organic light-emitting diodes using embedded silver network transparent electrodes.

    Science.gov (United States)

    Zhou, Lei; Xiang, Heng-Yang; Shen, Su; Li, Yan-Qing; Chen, Jing-De; Xie, Hao-Jun; Goldthorpe, Irene A; Chen, Lin-Sen; Lee, Shuit-Tong; Tang, Jian-Xin

    2014-12-23

    Because of their mechanical flexibility, organic light-emitting diodes (OLEDs) hold great promise as a leading technology for display and lighting applications in wearable electronics. The development of flexible OLEDs requires high-quality transparent conductive electrodes with superior bendability and roll-to-roll manufacturing compatibility to replace indium tin oxide (ITO) anodes. Here, we present a flexible transparent conductor on plastic with embedded silver networks which is used to achieve flexible, highly power-efficient large-area green and white OLEDs. By combining an improved outcoupling structure for simultaneously extracting light in waveguide and substrate modes and reducing the surface plasmonic losses, flexible white OLEDs exhibit a power efficiency of 106 lm W(-1) at 1000 cd m(-2) with angular color stability, which is significantly higher than all other reports of flexible white OLEDs. These results represent an exciting step toward the realization of ITO-free, high-efficiency OLEDs for use in a wide variety of high-performance flexible applications.

  10. Exploration of the horizontally staggered light guides for high concentration CPV applications.

    Science.gov (United States)

    Selimoglu, Ozgur; Turan, Rasit

    2012-08-13

    The material and processing costs are still the major drawbacks of the c-Si based photovoltaic (PV) technology. The wafer cost comprises up to 35-40% of the total module cost. New approaches and system designs are needed in order to reduce the share of the wafer cost in photovoltaic energy systems. Here we explore the horizontally staggered light guide solar optics for use in Concentrated Photovoltaic (CPV) applications. This optical system comprises a lens array system coupled to a horizontal light guide which directs the incoming light beam to its edge. We have designed and simulated this system using a commercial ray tracing software (Zemax). The system is more compact, thinner and more robust compared to the conventional CPV systems. Concentration levels as high as 1000x can easily be reached when the system is properly designed. With such a high concentration level, a good acceptance angle of + -1 degree is still be conserved. The analysis of the system reveals that the total optical efficiency of the system could be as high as %94.4 without any anti-reflection (AR) coating. Optical losses can be reduced by just accommodating a single layer AR coating on the initial lens array leading to a %96.5 optical efficiency. Thermal behavior of high concentration linear concentrator is also discussed and compared with a conventional point focus CPV system.

  11. Highly Efficient Soluble Blue Delayed Fluorescent and Hyperfluorescent Organic Light-Emitting Diodes by Host Engineering.

    Science.gov (United States)

    Jeon, Sang Kyu; Park, Hee-Jun; Lee, Jun Yeob

    2018-01-30

    Solution-processed high-efficiency fluorescent organic light-emitting diodes with an external quantum efficiency over 18% were developed by engineering a host material and device structure designed for solution process. A high triplet energy host material designed for the solution process, (oxybis(3-(tert-butyl)-6,1-phenylene))bis(diphenylphosphine oxide) (DPOBBPE), worked efficiently as the host of blue fluorescent devices because of good solubility, high photoluminescence quantum yield, and good film properties. The DPOBBPE host enabled a high external quantum efficiency of 18.8% in the fluorescent organic light-emitting diodes by the solution process. Moreover, 25.8% external quantum efficiency in the soluble blue thermally activated delayed fluorescent devices was also realized. The 25.8% external quantum efficiency of the DPOBBPE delayed fluorescent device and 18.8% external quantum efficiency of the fluorescent device are the highest efficiency values achieved in the solution-processed blue fluorescent organic light-emitting diodes. Moreover, the solution-processed fluorescent device showed an improved blue color coordinate of (0.14, 0.20) compared to (0.17, 0.31) of the delayed fluorescent device.

  12. High-resolution two-dimensional image upconversion of incoherent light

    DEFF Research Database (Denmark)

    Dam, Jeppe Seidelin; Pedersen, Christian; Tidemand-Lichtenberg, Peter

    2010-01-01

    We consider a technique for high-resolution image upconversion of thermal light. Experimentally, we demonstrate cw upconversion with a resolution of more than 200 × 1000 pixels of thermally illuminated objects. This is the first demonstration (to our knowledge) of high-resolution cw image...... upconversion. The upconversion method promises an alternative route to high-quantum-efficiency all-optical imaging in the mid-IR wavelength region and beyond using standard CCD cameras. A particular advantage of CCD cameras compared to state-of-the-art thermal cameras is the possibility to tailor and tune...... the spectral response leading to functional spectral imaging....

  13. Theoretical studies of possible toroidal high-spin isomers in the light-mass region

    Directory of Open Access Journals (Sweden)

    Staszczak Andrzej

    2016-01-01

    Full Text Available We review our theoretical knowledge of possible toroidal high-spin isomers in the light mass region in 28≤A≤52 obtained previously in cranked Skyrme-Hartree-Fock calculations. We report additional toroidal high-spin isomers in 56Ni with I=114ħ and 140ħ, which follow the same (multi-particle–(multi-hole systematics as other toroidal high-spin isomers. We examine the production of these exotic nuclei by fusion of various projectiles on 20Ne or 28Si as an active target in time-projection-chamber (TPC experiments.

  14. Strategies to Achieve High-Performance White Organic Light-Emitting Diodes

    Directory of Open Access Journals (Sweden)

    Lirong Zhang

    2017-12-01

    Full Text Available As one of the most promising technologies for next-generation lighting and displays, white organic light-emitting diodes (WOLEDs have received enormous worldwide interest due to their outstanding properties, including high efficiency, bright luminance, wide viewing angle, fast switching, lower power consumption, ultralight and ultrathin characteristics, and flexibility. In this invited review, the main parameters which are used to characterize the performance of WOLEDs are introduced. Subsequently, the state-of-the-art strategies to achieve high-performance WOLEDs in recent years are summarized. Specifically, the manipulation of charges and excitons distribution in the four types of WOLEDs (fluorescent WOLEDs, phosphorescent WOLEDs, thermally activated delayed fluorescent WOLEDs, and fluorescent/phosphorescent hybrid WOLEDs are comprehensively highlighted. Moreover, doping-free WOLEDs are described. Finally, issues and ways to further enhance the performance of WOLEDs are briefly clarified.

  15. Design and Dynamic Analysis of a High-Speed Organic Light-Emitting Diode

    Science.gov (United States)

    Salehifar, Samira; Shayesteh, Mohammad Reza; Hashemian, Saeedeh

    2018-02-01

    We propose a structure of a high-speed multilayer organic light-emitting diode (OLED). The different organic materials have been chosen so that the barrier potential between two adjacent layers is smaller than 0.2 eV, which causes the charge carriers to move easily between layers to reach the emitting layer. The static and dynamic behaviors of the OLED have been analyzed numerically. The results from simulation show that the proposed OLED structure has an electroluminescence delay time of about 30 ns, and hence can respond to electrical pulses with a repetition rate of 2 MHz. Moreover, the device can provide good features such as high light emission efficiency, low voltage DC driving, and thermal stability.

  16. Multilayer tungsten-alumina-based broadband light absorbers for high-temperature applications

    DEFF Research Database (Denmark)

    Chirumamilla, Manohar; Roberts, Alexander; Ding, Fei

    2016-01-01

    for the fabricated MIM resonator. Excellent thermal stability of the absorber is demonstrated at high operating temperatures (800 °C). The experimental broadband absorption spectra show good agreement with simulations. The resonator with 12 nm top tungsten and 100 nm alumina spacer film shows absorbance above 95...... the potential for a wide range of applications, including the use in commonly used infrared bands or absorbers for (solar) thermo-photovoltaic energy conversion, where high absorbance and simultaneously low (thermal) re-radiation is of paramount importance.......Efficient broadband absorption of visible and near-infrared light by low quality-factor metal-insulator-metal (MIM) resonators using refractory materials is reported. Omnidirectional absorption of incident light for broad angles of incidence and polarization insensitivity are observed...

  17. HPS (high pressure sodium) lighting for winter greenhouse cucumber production. B. C. commercial scale demonstration

    Energy Technology Data Exchange (ETDEWEB)

    Crocker, B.; Dyble, C.; Hughes, R.

    1988-01-01

    The purpose of this project was to expand on the earlier research work to demonstrate the economics of commercial scale producation and marketing of long English cucumbers in a commercial greenhouse environment. Artificial lighting was used to supplement the winter daylight, and consisted of High Pressure Sodium 400 watt lamps, with high efficiency luminaires. The luminaires were located throughout the greenhouse to achieve an average supplemental illumination level of 5000 lux within the plant canopy in a 1700 m/sup 2/ greenhouse. This report identifies the crop results and describes the lighting configuration, the method of monitoring of the environmental factors, and the analysis of the results. Conclusions suggest that differences in winter supplemental radiation compared to summer radiation, affect plant growth, nutrient absorption, humidity control, and pest control. Conclusions are provided including extrapolated economic analyses, and recommendations are given concerning future investigations. 42 figs., 13 tabs.

  18. Effect of very high magnetic field on the optical properties of firefly light emitter oxyluciferin

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Weihang; Nakamura, Daisuke [Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581 (Japan); Wang, Yu [Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581 (Japan); State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences (China); Mochizuki, Toshimitsu [Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581 (Japan); Fukushima Renewable Energy Institute, National Institute of Advanced Industrial Science and Technology, 2-2-9 Machiike-dai, Koriyama, Fukushima 963-0215 (Japan); Akiyama, Hidefumi [Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581 (Japan); Takeyama, Shojiro, E-mail: takeyama@issp.u-tokyo.ac.jp [Institute for Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581 (Japan)

    2015-09-15

    Magnetic field effect on enzymatic reactions is under intensive study in the past decades. Recently, it was reported that firefly bioluminescence was suppressed and red-shifted significantly when exposed to external magnetic field. However in this work, by means of selective excitation, we confirmed that emission properties of firefly light emitter “oxyluciferin” are completely immune to external magnetic field of up to 53 T. These findings pose strong contrast to existing relevant results. Potential reasons for the discrepancies found and the underlying physics towards the understanding of firefly bioluminescence were discussed. - Highlights: • Effect of ultra-high magnetic field on the optical properties of firefly light emitter oxyluciferin was reported. • Emission properties of oxyluciferin were confirmed to be immune to external high magnetic fields up to 53 T. • .Potential reasons for the discrepancies between our results and previous reports and the underlying physics were discussed.

  19. Radiation Hard and High Light Yield Scintillator Search for CMS Phase II Upgrade

    CERN Document Server

    Tiras, Emrah

    2015-01-01

    The CMS detector at the LHC requires a major upgrade to cope with the higher instantaneous luminosity and the elevated radiation levels. The active media of the forward backing hadron calorimeters is projected to be radiation-hard, high light yield scintillation materials or similar alternatives. In this context, we have studied various radiation-hard scintillating materials such as Polyethylene Terephthalate (PET), Polyethylene Naphthalate (PEN), High Efficiency Mirror (HEM) and quartz plates with various coatings. The quartz plates are pure Cerenkov radiators and their radiation hardness has been confirmed. In order to increase the light output, we considered organic and inorganic coating materials such as p-Terphenyl (pTp), Anthracene and Gallium-doped Zinc Oxide (ZnO Ga) that are applied as thin layers on the surface of the quartz plates. Here, we present the results of the related test beam activities, laboratory measurements and recent developments.

  20. A high-power spatial filter for Thomson scattering stray light reduction

    Science.gov (United States)

    Levesque, J. P.; Litzner, K. D.; Mauel, M. E.; Maurer, D. A.; Navratil, G. A.; Pedersen, T. S.

    2011-03-01

    The Thomson scattering diagnostic on the High Beta Tokamak-Extended Pulse (HBT-EP) is routinely used to measure electron temperature and density during plasma discharges. Avalanche photodiodes in a five-channel interference filter polychromator measure scattered light from a 6 ns, 800 mJ, 1064 nm Nd:YAG laser pulse. A low cost, high-power spatial filter was designed, tested, and added to the laser beamline in order to reduce stray laser light to levels which are acceptable for accurate Rayleigh calibration. A detailed analysis of the spatial filter design and performance is given. The spatial filter can be easily implemented in an existing Thomson scattering system without the need to disturb the vacuum chamber or significantly change the beamline. Although apertures in the spatial filter suffer substantial damage from the focused beam, with proper design they can last long enough to permit absolute calibration.

  1. Self-focusing and filamentation of laser light in high Z plasmas

    Science.gov (United States)

    Jones, R. D.; Mead, W. C.; Coggeshall, S. V.; Aldrich, C. H.; Norton, J. L.; Pollak, G. D.; Wallace, J. M.

    1988-05-01

    Self-focusing and filamentation of short wavelength laser light in high Z plasmas of interest to laser fusion are discussed. It is found that self-focusing behavior is very dependent on the details of the characteristics of the laser beam, the plasma conditions, and the energy transport processes. Laser light absorption and self-focusing are strongly competitive processes. At. 0.26 μm wavelength the collisional absorption is often so great that there is no intensity amplification of the beam despite the fact that strong self-focusing is present. Wide variations are found in laser light penetration, affected by several factors. Diverging optics reduce the likelihood of self-focusing. Large scale length density gradients have little effect on focusing behavior. The self-focusing behavior is very dependent on beam shape. Large scale hot spots can have a significant effect on whole beam self-focusing early in the pulse. The behavior of small scale hot spots can be qualitatively different than the standard picture. The calculations indicate that small scale hot spots do not achieve a steady state in some cases. Sound waves cause chaotic interactions among neighboring hot spots. It is found that sub-beam size structures are also generated when nonlocal thermodynamic equilibrium (non-LTE) radiation and atomic physics are used in the calculations. The nature of the heat flux and thermoelectric magnetic field generation are examined with a kinetic model. Stimulated Raman backscattering levels in self-focused light are significantly reduced for short wavelengths and high Z plasmas Landau damping plays an important role in determining the Raman levels. Implications for suprathermal electron production, symmetric illumination, x-ray conversion efficiency, and laser light absorption are discussed.

  2. Curing efficiency of high-intensity light-emitting diode (LED) devices.

    Science.gov (United States)

    Rahiotis, Christos; Patsouri, Katerina; Silikas, Nick; Kakaboura, Afrodite

    2010-06-01

    We evaluated the curing efficiency of 4 high-intensity light-emitting diode (LED) devices by assessing percentage of residual C=C (%RDB), surface microhardness (SM), depth of cure (DC), percentage of linear shrinkage-strain (%LS), and percentage of wall-to-wall contraction (%WWC). The light-curing units tested were a QTH light, the Elipar TriLight (3M/ESPE), and 4 LED devices - the Allegro (Denmat), the Bluephase (Ivoclar/Vivadent), the FreeLight2 (3M/ESPE), and The Cure TC-01 (Spring Health Products). The %RDB was measured by microFTIR spectroscopy. Microhardness measurements (Vickers) were performed at the surface (H0) and at depths of 3 mm (H3) and 5 mm (H5) of cylindrical specimens. Depth of cure was expressed as the ratio of microhardness at each depth, relative to the corresponding surface value (H3/H0 and H5/H0). The bonded disc method was used to evaluate %LS. For the %WWC evaluation, cylindrical resin restorations were imaged by high resolution micro-CT and the %WWC was calculated at depths of 0 mm and 2 mm. There were no statistical differences among the LEDs in %RDB or %LS. The Bluephase and Allegro had the highest SM values. As compared with the other LEDs, the Bluephase and The Cure TC-01 had lower values for depth of cure at depths of 3 mm and 5 mm. There were no significant differences in %WWC among the LEDs at either depth, and the QTH had the lowest %WWC at both depths.

  3. Quantum dots/silica/polymer nanocomposite films with high visible light transmission and UV shielding properties

    Science.gov (United States)

    Mumin, Md Abdul; Xu, William Z.; Charpentier, Paul A.

    2015-08-01

    The dispersion of light-absorbing inorganic nanomaterials in transparent plastics such as poly(ethylene-co-vinyl acetate) (PEVA) is of enormous current interest in emerging solar materials, including photovoltaic (PV) modules and commercial greenhouse films. Nanocrystalline semiconductor or quantum dots (QDs) have the potential to absorb UV light and selectively emit visible light, which can control plant growth in greenhouses or enhance PV panel efficiencies. This work provides a new and simple approach for loading mesoporous silica-encapsulated QDs into PEVA. Highly luminescent CdS and CdS-ZnS core-shell QDs with 5 nm size were synthesized using a modified facile approach based on pyrolysis of the single-molecule precursors and capping the CdS QDs with a thin layer of ZnS. To make both the bare and core-shell structure QDs more resistant against photochemical reactions, a mesoporous silica layer was grown on the QDs through a reverse microemulsion technique based on hydrophobic interactions. By careful experimental tuning, this encapsulation technique enhanced the quantum yield (˜65%) and photostability compared to the bare QDs. Both the encapsulated bare and core-shell QDs were then melt-mixed with EVA pellets using a mini twin-screw extruder and pressed into thin films with controlled thickness. The results demonstrated for the first time that mesoporous silica not only enhanced the quantum yield and photostability of the QDs but also improved the compatibility and dispersibility of QDs throughout the PEVA films. The novel light selective films show high visible light transmission (˜90%) and decreased UV transmission (˜75%).

  4. LightAssembler: fast and memory-efficient assembly algorithm for high-throughput sequencing reads.

    Science.gov (United States)

    El-Metwally, Sara; Zakaria, Magdi; Hamza, Taher

    2016-11-01

    The deluge of current sequenced data has exceeded Moore's Law, more than doubling every 2 years since the next-generation sequencing (NGS) technologies were invented. Accordingly, we will able to generate more and more data with high speed at fixed cost, but lack the computational resources to store, process and analyze it. With error prone high throughput NGS reads and genomic repeats, the assembly graph contains massive amount of redundant nodes and branching edges. Most assembly pipelines require this large graph to reside in memory to start their workflows, which is intractable for mammalian genomes. Resource-efficient genome assemblers combine both the power of advanced computing techniques and innovative data structures to encode the assembly graph efficiently in a computer memory. LightAssembler is a lightweight assembly algorithm designed to be executed on a desktop machine. It uses a pair of cache oblivious Bloom filters, one holding a uniform sample of [Formula: see text]-spaced sequenced [Formula: see text]-mers and the other holding [Formula: see text]-mers classified as likely correct, using a simple statistical test. LightAssembler contains a light implementation of the graph traversal and simplification modules that achieves comparable assembly accuracy and contiguity to other competing tools. Our method reduces the memory usage by [Formula: see text] compared to the resource-efficient assemblers using benchmark datasets from GAGE and Assemblathon projects. While LightAssembler can be considered as a gap-based sequence assembler, different gap sizes result in an almost constant assembly size and genome coverage. https://github.com/SaraEl-Metwally/LightAssembler CONTACT: sarah_almetwally4@mans.edu.egSupplementary information: Supplementary data are available at Bioinformatics online. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  5. Metasurface integrated high energy efficient and high linearly polarized InGaN/GaN light emitting diode.

    Science.gov (United States)

    Wang, Miao; Xu, Fuyang; Lin, Yu; Cao, Bing; Chen, Linghua; Wang, Chinhua; Wang, Jianfeng; Xu, Ke

    2017-07-06

    We proposed and demonstrated an integrated high energy efficient and high linearly polarized InGaN/GaN green LED grown on (0001) oriented sapphire with combined metasurface polarizing converter and polarizer system. It is different from those conventional polarized light emissions generated with plasmonic metallic grating in which at least 50% high energy loss occurs inherently due to high reflection of the transverse electric (TE) component of an electric field. A reflecting metasurface, with a two dimensional elliptic metal cylinder array (EMCA) that functions as a half-wave plate, was integrated at the bottom of a LED such that the back-reflected TE component, that is otherwise lost by a dielectric/metal bi-layered wire grids (DMBiWG) polarizer on the top emitting surface of the LED, can be converted to desired transverse magnetic (TM) polarized emission after reflecting from the metasurface. This significantly enhances the polarized light emission efficiency. Experimental results show that extraction efficiency of the polarized emission can be increased by 40% on average in a wide angle of ±60° compared to that with the naked bottom of sapphire substrate, or 20% compared to reflecting Al film on the bottom of a sapphire substrate. An extinction ratio (ER) of average value 20 dB within an angle of ±60° can be simultaneously obtained directly from an InGaN/GaN LED. Our results show the possibility of simultaneously achieving a high degree of polarization and high polarization extraction efficiency at the integrated device level. This advances the field of GaN LED toward energy efficiency, multi-functional applications in illumination, display, medicine, and light manipulation.

  6. Study on the Use of Hydride Fuel in High-Performance Light Water Reactor Concept

    OpenAIRE

    Haileyesus Tsige-Tamirat; Luca Ammirabile

    2015-01-01

    Hydride fuels have features which could make their use attractive in future advanced power reactors. The potential benefit of use of hydride fuel in HPLWR without introducing significant modification in the current core design concept of the high-performance light water reactor (HPLWR) has been evaluated. Neutronics and thermal hydraulic analyses were performed for a single assembly model of HPLWR with oxide and hydride fuels. The hydride assembly shows higher moderation with softer neutron s...

  7. Development of High-Strength Nanostructured Magnesium Alloys for Light-Weight Weapon Systems and Vehicles

    Science.gov (United States)

    2014-01-13

    University of California - Los Angeles Office of Contract and Grant Administration 11000 Kinross Avenue, Suite 102 Los Angeles, CA 90095 -1406...Wollersheim, and R. Wurschum. Acta Mater. 49, 737 (2001). 2. Y. Champion, C. Langlois, S. Guerin -Mailly, P. Langlois, J.-L. Bonnentien, and M.J. Hytch...Angeles, Los Angeles, CA 90095 Development of High-Strength Nanostructured Magnesium Alloys for Light-Weight Weapon Systems and Vehicles

  8. Highly Efficient Perovskite-Quantum-Dot Light-Emitting Diodes by Surface Engineering

    KAUST Repository

    Pan, Jun

    2016-08-16

    A two-step ligand-exchange strategy is developed, in which the long-carbon-chain ligands on all-inorganic perovskite (CsPbX3, X = Br, Cl) quantum dots (QDs) are replaced with halide-ion-pair ligands. Green and blue light-emitting diodes made from the halide-ion-paircapped quantum dots exhibit high external quantum efficiencies compared with the untreated QDs.

  9. Photoinhibition of photosystem I under high light in the shade-established tropical tree species Psychotria rubra

    Directory of Open Access Journals (Sweden)

    Wei eHuang

    2015-09-01

    Full Text Available The photosynthetic sensitivity to high light differs among understory plants of shade- and sun- established tree species. Shade-established tree species are sensitive to high light but the underlying photosynthetic mechanism has not been fully resolved. In the present study, we examined the responses of photosystem I (PSI and photosystem II (PSII to high light in shade leaves of a shade-established tree species Psychotria rubra and a sun-established tree species Pometia tomentosa. After exposure to 2000 μmol photons m−2 s−1 for 2 h, the maximum photo-oxidizable P700 (Pm decreased by 40% and 9% in P. rubra and P. tomentosa, respectively. These results indicate that the shade-established species P. rubra is incapable of protecting PSI under high light. Strong photoinhibition of PSII under high light led to large depression of electron transfer from PSII to PSI and then prevented further photodamage to PSI. During the high light treatment of 2000 μmol photons m−2 s−1, PSI photoinhibition in P. rubra was accompanied with high levels of cyclic electron flow (CEF and P700 oxidation ratio. Therefore, we propose that PSI photoinhibition under high light in P. rubra is dependent on electron transfer from PSII to PSI, and CEF is unlikely to play a major role in photoprotection for PSI in P. rubra. These findings suggest that photoinhibition of PSI is another important mechanism underlying why shade-established species cannot survive under high light.

  10. Dynamic Acclimation to High Light in Arabidopsis thaliana Involves Widespread Reengineering of the Leaf Proteome

    Directory of Open Access Journals (Sweden)

    Matthew A. E. Miller

    2017-07-01

    Full Text Available Leaves of Arabidopsis thaliana transferred from low to high light increase their capacity for photosynthesis, a process of dynamic acclimation. A mutant, gpt2, lacking a chloroplast glucose-6-phosphate/phosphate translocator, is deficient in its ability to acclimate to increased light. Here, we have used a label-free proteomics approach, to perform relative quantitation of 1993 proteins from Arabidopsis wild type and gpt2 leaves exposed to increased light. Data are available via ProteomeXchange with identifier PXD006598. Acclimation to light is shown to involve increases in electron transport and carbon metabolism but no change in the abundance of photosynthetic reaction centers. The gpt2 mutant shows a similar increase in total protein content to wild type but differences in the extent of change of certain proteins, including in the relative abundance of the cytochrome b6f complex and plastocyanin, the thylakoid ATPase and selected Benson-Calvin cycle enzymes. Changes in leaf metabolite content as plants acclimate can be explained by changes in the abundance of enzymes involved in metabolism, which were reduced in gpt2 in some cases. Plants of gpt2 invest more in stress-related proteins, suggesting that their reduced ability to acclimate photosynthetic capacity results in increased stress.

  11. Development of a High Output Fluorescent Light Module for the Commercial Plant Biotechnology Facility

    Science.gov (United States)

    Turner, Mark; Zhou, Wei-Jia; Doty, Laura (Technical Monitor)

    2000-01-01

    To maximize the use of available resources provided onboard the International Space Station, the development of an efficient lighting 1 system is critical to the overall performance of the CPBF. Not only is it important to efficiently generate photon energy, but thermal loads on the CPBF Temperature and Humidity Control System must be minimized. By utilizing optical coatings designed to produce highly diffuse reflectance in the visible wavelengths while minimizing reflectance in the infrared region, the design of the fluorescent light module for the CPBF is optimized for maximum photon flux, spatial uniformity and energy efficiency. Since the Fluorescent Light Module must be fully enclosed to meet (ISS) requirements for containment of particulates and toxic materials, heat removal from the lights presented some unique design challenges. By using the Express Rack moderate C, temperature-cooling loop, heat is rejected by means of a liquid/air coolant manifold. Heat transfer to the manifold is performed by conduction using copper fins, by forced air convection using miniature fans, and by radiation using optically selective coatings that absorb in the infrared wavelengths. Using this combination of heat transfer mechanisms builds in redundancy to prevent thermal build up and premature bulb failure.

  12. Ultraviolet Plasmonic Aluminium Nanoparticles for Highly Efficient Light Incoupling on Silicon Solar Cells

    Directory of Open Access Journals (Sweden)

    Yinan Zhang

    2016-05-01

    Full Text Available Plasmonic metal nanoparticles supporting localized surface plasmon resonances have attracted a great deal of interest in boosting the light absorption in solar cells. Among the various plasmonic materials, the aluminium nanoparticles recently have become a rising star due to their unique ultraviolet plasmonic resonances, low cost, earth-abundance and high compatibility with the complementary metal-oxide semiconductor (CMOS manufacturing process. Here, we report some key factors that determine the light incoupling of aluminium nanoparticles located on the front side of silicon solar cells. We first numerically study the scattering and absorption properties of the aluminium nanoparticles and the influence of the nanoparticle shape, size, surface coverage and the spacing layer on the light incoupling using the finite difference time domain method. Then, we experimentally integrate 100-nm aluminium nanoparticles on the front side of silicon solar cells with varying silicon nitride thicknesses. This study provides the fundamental insights for designing aluminium nanoparticle-based light trapping on solar cells.

  13. 49 CFR Appendix C to Part 541 - Criteria for Selecting Light Duty Truck Lines Likely To Have High Theft Rates

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 6 2010-10-01 2010-10-01 false Criteria for Selecting Light Duty Truck Lines Likely To Have High Theft Rates C Appendix C to Part 541 Transportation Other Regulations Relating to... Light Duty Truck Lines Likely To Have High Theft Rates Scope These criteria specify the factors the...

  14. Stress analysis of the reactor pressure vessel of the high performance light water reactors (HPLWR); Festigkeitsanalyse fuer den Reaktordruckbehaelter des High Performance Light Water Reactor (HPLWR)

    Energy Technology Data Exchange (ETDEWEB)

    Guelton, E.; Fischer, K.

    2006-12-15

    The High Performance Light Water Reactor (HPLWR) is one of the concepts of the Generation IV program. The main difference compared to current Light Water Reactors (LWR) results from the supercritical steam condition of the coolant. Due to the supercritical pressure of 25 MPa, water, used as moderator and coolant, flows as a single phase through the core. The temperatures at the outlet are above 500 C. These conditions have a major impact on the design of the Reactor Pressure Vessel (RPV). For the modelling a RPV concept is proposed, which resembles the design of current LWR and allows the use of approved materials on one side and also meets the additional demands on the other side. A first dimensioning of the RPV wall thicknesses and the geometrical proportions has been performed using the german KTA-guidelines. To verify these results, a stress analysis using the finite element method has been performed with the program ANSYS. The combined mechanical and thermal calculations provide the primary, secondary and peak stresses which are evaluated using the KTA-guidelines design loading (Level 0) and service loading level A for the different components. The results confirm the wall thicknesses estimated by Fischer et al. (2006), but there are peak stresses in the vicinity of the inlet and outlet flanges, which are very close to the allowed design limit. For larger diameters of the RPV those regions will become critical and the stresses might exceed the design limits. Design optimizations for those regions are proposed and evaluated. A readjusted geometry of the inlet flange reduces those stresses by 65%. (orig.)

  15. Reducing Barriers To The Use of High-Efficiency Lighting Systems

    Energy Technology Data Exchange (ETDEWEB)

    Peter Morante

    2005-12-31

    With funding from the U.S. Department of Energy (DOE), the Lighting Research Center (LRC) at Rensselaer Polytechnic Institute completed the four-year research project, Reducing Barriers to the Use of High-Efficiency Lighting Systems. The initial objectives were: (1) identifying barriers to widespread penetration of lighting controls in commercial/industrial (C/I) applications that employ fluorescent lamp technologies, and (2) making recommendations to overcome these barriers. The addition of a fourth year expanded the original project objectives to include an examination of the impact on fluorescent lamps from dimming utilizing different lamp electrode heating and dimming ratios. The scope of the project was narrowed to identify barriers to the penetration of lighting controls into commercial-industrial (C/I) applications that employ fluorescent lamp technologies, and to recommend means for overcoming these barriers. Working with lighting manufacturers, specifiers, and installers, the project identified technological and marketing barriers to the widespread use of lighting controls, specifically automatic-off controls, occupancy sensors, photosensors, dimming systems, communication protocols and load-shedding ballasts. The primary barriers identified include cost effectiveness of lighting controls to the building owner, lack of standard communication protocols to allow different part of the control system to communicate effectively, and installation and commissioning issues. Overcoming the identified barriers requires lighting control products on the market to achieve three main goals: (1) Achieve sufficient functionality to meet the key requirements of their main market. (2) Allow significant cost reduction compared to current market standard systems. Cost should consider: hardware capital cost including wiring, design time required by the specifier and the control system manufacturer, installation time required by the electrician, and commissioning time and

  16. Dynamic miniature lighting system with low correlated colour temperature and high colour rendering index for museum lighting of fragile artefacts

    DEFF Research Database (Denmark)

    Thorseth, Anders; Corell, Dennis Dan; Poulsen, Peter Behrensdorff

    2013-01-01

    of historical artefacts in display cases at museums and other exhibitions, which can replace 3-5 Watt incandescent light bulbs with a correlated colour temperature (CCT) from 2000 K to 2400 K. The solution decreases the energy consumption by up to 80 %, while maintaining colour rendering indices (Ra) above 90...

  17. Development of Advanced High Uranium Density Fuels for Light Water Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Blanchard, James [Univ. of Wisconsin, Madison, WI (United States); Butt, Darryl [Boise State Univ., ID (United States); Meyer, Mitchell [Idaho National Lab. (INL), Idaho Falls, ID (United States); Xu, Peng [Westinghouse Electric Corporation, Pittsburgh, PA (United States)

    2016-02-15

    This work conducts basic materials research (fabrication, radiation resistance, thermal conductivity, and corrosion response) on U3Si2 and UN, two high uranium density fuel forms that have a high potential for success as advanced light water reactor (LWR) fuels. The outcome of this proposed work will serve as the basis for the development of advance LWR fuels, and utilization of such fuel forms can lead to the optimization of the fuel performance related plant operating limits such as power density, power ramp rate and cycle length.

  18. Science from the Avo 1ST Light: the High Redshift Universe

    Science.gov (United States)

    Walton, Nicholas A.

    The Astrophysical Virtual Observatory science working group defined a number of key science drivers for which the AVO should develop capabilities. At the AVO's Jan 2003 'First Light' event the AVO prototype data access and manipulation tool was demonstrated. In particular its use in enabling discovery in deep multi wavelength data sets was highlighted. In this presentation I will describe how the AVO demonstrator has enabled investigation into the high redshift universe and in particular its use in discovering rare populations of high redshift galaxies from deep Hubble and ground based imaging data obtained through the Great Observatories Origins Deep Survey (GOODS) programme.

  19. Unlocking the full potential of conducting polymers for high-efficiency organic light-emitting devices.

    Science.gov (United States)

    Huang, Yi-Hsiang; Tsai, Wei-Lung; Lee, Wei-Kai; Jiao, Min; Lu, Chun-Yang; Lin, Chun-Yu; Chen, Chien-Yu; Wu, Chung-Chih

    2015-02-04

    By carefully tuning the thicknesses of low-optical index PEDOT:PSS and high-index ITO layers in organic light-emitting devices (OLEDs), very high optical coupling efficiencies can be obtained through the generation of appropriate microcavity effects. These experiments result in an external quantum efficiency (EQE) of 33.7% for green phosphorescent OLEDs and even higher EQEs of 54.3% can be obtained by adopting an external out-coupling lens. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Squeezed light for the interferometric detection of high-frequency gravitational waves

    Science.gov (United States)

    Schnabel, R.; Harms, J.; Strain, K. A.; Danzmann, K.

    2004-03-01

    The quantum noise of the light field is a fundamental noise source in interferometric gravitational-wave detectors. Injected squeezed light is capable of reducing the quantum noise contribution to the detector noise floor to values that surpass the so-called standard quantum limit (SQL). In particular, squeezed light is useful for the detection of gravitational waves at high frequencies where interferometers are typically shot-noise limited, although the SQL might not be beaten in this case. We theoretically analyse the quantum noise of the signal-recycled laser interferometric gravitational-wave detector GEO 600 with additional input and output optics, namely frequency-dependent squeezing of the vacuum state of light entering the dark port and frequency-dependent homodyne detection. We focus on the frequency range between 1 kHz and 10 kHz, where, although signal recycled, the detector is still shot-noise limited. It is found that the GEO 600 detector with present design parameters will benefit from frequency-dependent squeezed light. Assuming a squeezing strength of -6 dB in quantum noise variance, the interferometer will become thermal noise limited up to 4 kHz without further reduction of bandwidth. At higher frequencies the linear noise spectral density of GEO 600 will still be dominated by shot noise and improved by a factor of 106dB/20dB ap 2 according to the squeezing strength assumed. The interferometer might reach a strain sensitivity of 6 × 10-23 above 1 kHz (tunable) with a bandwidth of around 350 Hz. We propose a scheme to implement the desired frequency-dependent squeezing by introducing an additional optical component into GEO 600's signal-recycling cavity.

  1. A high-speed, eight-wavelength visible light-infrared pyrometer for shock physics experiments

    Directory of Open Access Journals (Sweden)

    Rongbo Wang

    2017-09-01

    Full Text Available An eight-channel, high speed pyrometer for precise temperature measurement is designed and realized in this work. The addition of longer-wavelength channels sensitive at lower temperatures highly expands the measured temperature range, which covers the temperature of interest in shock physics from 1500K-10000K. The working wavelength range is 400-1700nm from visible light to near-infrared (NIR. Semiconductor detectors of Si and InGaAs are used as photoelectric devices, whose bandwidths are 50MHz and 150MHz respectively. Benefitting from the high responsivity and high speed of detectors, the time resolution of the pyrometer can be smaller than 10ns. By combining the high-transmittance beam-splitters and narrow-bandwidth filters, the peak spectrum transmissivity of each channel can be higher than 60%. The gray-body temperatures of NaI crystal under shock-loading are successfully measured by this pyrometer.

  2. A high-power incoherent light source for ultra-precise optical trapping

    Science.gov (United States)

    Schittko, Robert; Mazurenko, Anton; Greiner, Markus

    2016-05-01

    The ability to engineer arbitrary optical potentials using spatial light modulation has opened up exciting possibilities in ultracold quantum gas experiments. Yet, despite the high trap quality currently achievable, interference-induced distortions caused by scattering along the optical path continue to impede more sensitive measurements. We present a design of a high-power, spatially and temporally incoherent light source that dramatically reduces the impact of such distortions. The device is based on an array of non-lasing semiconductor emitters mounted on a single chip, whose optical output is coupled into a multi-mode fiber. The fiber is used to populate a large number of transverse modes, each of which experiences a different optical path length. This effect, combined with the small coherence length of the light, dramatically reduces the spatial coherence of the output. In addition to theoretical calculations showcasing the feasibility of this approach, we present various experimental measurements verifying the low degree of spatial coherence exhibited by the source, including a detailed analysis of the speckle contrast at the fiber end.

  3. Integrated High Resolution Digital Color Light Sensor in 130 nm CMOS Technology.

    Science.gov (United States)

    Strle, Drago; Nahtigal, Uroš; Batistell, Graciele; Zhang, Vincent Chi; Ofner, Erwin; Fant, Andrea; Sturm, Johannes

    2015-07-22

    This article presents a color light detection system integrated in 130 nm CMOS technology. The sensors and corresponding electronics detect light in a CIE XYZ color luminosity space using on-chip integrated sensors without any additional process steps, high-resolution analog-to-digital converter, and dedicated DSP algorithm. The sensor consists of a set of laterally arranged integrated photodiodes that are partly covered by metal, where color separation between the photodiodes is achieved by lateral carrier diffusion together with wavelength-dependent absorption. A high resolution, hybrid, ∑∆ ADC converts each photo diode's current into a 22-bit digital result, canceling the dark current of the photo diodes. The digital results are further processed by the DSP, which calculates normalized XYZ or RGB color and intensity parameters using linear transformations of the three photo diode responses by multiplication of the data with a transformation matrix, where the coefficients are extracted by training in combination with a pseudo-inverse operation and the least-mean square approximation. The sensor system detects the color light parameters with 22-bit accuracy, consumes less than 60 μA on average at 10 readings per second, and occupies approx. 0.8 mm(2) of silicon area (including three photodiodes and the analog part of the ADC). The DSP is currently implemented on FPGA.

  4. High sensitivity electro-optic modulation of slow light in ellipse rods PC-CROW

    Science.gov (United States)

    Li, Changhong; Wan, Yong; Zong, Weihua

    2017-07-01

    A tunable slow light with low group velocity, high buffer performance and high sensitivity is realized in photonic crystal coupled resonator optical waveguide (PC-CROW) with elliptical rod around cavity. By adjusting the long axis and short axis of the elliptical rods, the slow light and buffer performance of PC-CROW are optimized. As ae=0.42a, be=0.20a, the group velocity is below 2.3053×10-4c, simultaneously, the buffer capacity C and delay time Ts reach the optimum value of 9.8214 bit and 354.8 ps. Then the dynamic modulation of the slow light and buffer performance based on this optimized structure has been discussed systematically. Thanks to the electro-optic effect of the polystyrene substrate, the guided mode shifts linearly to short wavelength in sensitivity of 3.0 nm/mV around 1550 nm, as the applied voltage increases. The modulation sensitivities of delay time and buffer capacity are 0.445 ns/mV and 0.051 bit/mV, respectively. These results show a considerable potential for this structure that can be dynamically controlled according to the practical requirements by electro-optic effect in PC-CROW.

  5. Integrated High Resolution Digital Color Light Sensor in 130 nm CMOS Technology

    Directory of Open Access Journals (Sweden)

    Drago Strle

    2015-07-01

    Full Text Available This article presents a color light detection system integrated in 130 nm CMOS technology. The sensors and corresponding electronics detect light in a CIE XYZ color luminosity space using on-chip integrated sensors without any additional process steps, high-resolution analog-to-digital converter, and dedicated DSP algorithm. The sensor consists of a set of laterally arranged integrated photodiodes that are partly covered by metal, where color separation between the photodiodes is achieved by lateral carrier diffusion together with wavelength-dependent absorption. A high resolution, hybrid, ∑∆ ADC converts each photo diode’s current into a 22-bit digital result, canceling the dark current of the photo diodes. The digital results are further processed by the DSP, which calculates normalized XYZ or RGB color and intensity parameters using linear transformations of the three photo diode responses by multiplication of the data with a transformation matrix, where the coefficients are extracted by training in combination with a pseudo-inverse operation and the least-mean square approximation. The sensor system detects the color light parameters with 22-bit accuracy, consumes less than 60 μA on average at 10 readings per second, and occupies approx. 0.8 mm2 of silicon area (including three photodiodes and the analog part of the ADC. The DSP is currently implemented on FPGA.

  6. Sub-high Temperature and High Light Intensity Induced Irreversible Inhibition on Photosynthesis System of Tomato Plant (Solanum lycopersicum L.).

    Science.gov (United States)

    Lu, Tao; Meng, Zhaojuan; Zhang, Guoxian; Qi, Mingfang; Sun, Zhouping; Liu, Yufeng; Li, Tianlai

    2017-01-01

    High temperature and high light intensity is a common environment posing a great risk to organisms. This study aimed to elucidate the effects of sub-high temperature and high light intensity stress (HH, 35°C, 1000 μmol⋅m(-2)⋅s(-1)) and recovery on the photosynthetic mechanism, photoinhibiton of photosystem II (PSII) and photosystem I (PSI), and reactive oxygen (ROS) metabolism of tomato seedlings. The results showed that with prolonged stress time, net photosynthetic rate (Pn), Rubisco activity, maximal photochemistry efficiency (Fv/Fm), efficient quantum yield and electron transport of PSII [Y(II) and ETR(II)] and PSI [Y(I) and ETR(I)] decreased significantly whereas yield of non-regulated and regulated energy dissipation of PSII [Y(NO) and Y(NPQ)] increased sharply. The donor side limitation of PSI [Y(ND)] increased but the acceptor side limitation of PSI [Y(NA)] decreased. Content of malondialdehyde (MDA) and hydrogen peroxide (H2O2) were increased while activity of superoxide dismutase (SOD) and peroxidase (POD) were significantly inhibited compared with control. HH exposure affected photosynthetic carbon assimilation, multiple sites in PSII and PSI, ROS accumulation and elimination of Solanum lycopersicum L.

  7. Near-infrared roll-off-free electroluminescence from highly stable diketopyrrolopyrrole light emitting diodes

    Science.gov (United States)

    Sassi, Mauro; Buccheri, Nunzio; Rooney, Myles; Botta, Chiara; Bruni, Francesco; Giovanella, Umberto; Brovelli, Sergio; Beverina, Luca

    2016-09-01

    Organic light emitting diodes (OLEDs) operating in the near-infrared spectral region are gaining growing relevance for emerging photonic technologies, such as lab-on-chip platforms for medical diagnostics, flexible self-medicated pads for photodynamic therapy, night vision and plastic-based telecommunications. The achievement of efficient near-infrared electroluminescence from solution-processed OLEDs is, however, an open challenge due to the low photoluminescence efficiency of most narrow-energy-gap organic emitters. Diketopyrrolopyrrole-boron complexes are promising candidates to overcome this limitation as they feature extremely high photoluminescence quantum yield in the near-infrared region and high chemical stability. Here, by incorporating suitably functionalized diketopyrrolopyrrole derivatives emitting at ~760 nm in an active matrix of poly(9,9-dioctylfluorene-alt-benzothiadiazole) and without using complex light out-coupling or encapsulation strategies, we obtain all-solution-processed NIR-OLEDs with external quantum efficiency as high as 0.5%. Importantly, our test-bed devices show no efficiency roll-off even for high current densities and high operational stability, retaining over 50% of the initial radiant emittance for over 50 hours of continuous operation at 10 mA/cm2, which emphasizes the great applicative potential of the proposed strategy.

  8. Deep blue phosphorescent organic light-emitting diodes with very high brightness and efficiency.

    Science.gov (United States)

    Lee, Jaesang; Chen, Hsiao-Fan; Batagoda, Thilini; Coburn, Caleb; Djurovich, Peter I; Thompson, Mark E; Forrest, Stephen R

    2016-01-01

    The combination of both very high brightness and deep blue emission from phosphorescent organic light-emitting diodes (PHOLED) is required for both display and lighting applications, yet so far has not been reported. A source of this difficulty is the absence of electron/exciton blocking layers (EBL) that are compatible with the high triplet energy of the deep blue dopant and the high frontier orbital energies of hosts needed to transport charge. Here, we show that N-heterocyclic carbene (NHC) Ir(III) complexes can serve as both deep blue emitters and efficient hole-conducting EBLs. The NHC EBLs enable very high brightness (>7,800 cd m(-2)) operation, while achieving deep blue emission with colour coordinates of [0.16, 0.09], suitable for most demanding display applications. We find that both the facial and the meridional isomers of the dopant have high efficiencies that arise from the unusual properties of the NHC ligand-that is, the complexes possess a strong metal-ligand bond that destabilizes the non-radiative metal-centred ligand-field states. Our results represent an advance in blue-emitting PHOLED architectures and materials combinations that meet the requirements of many critical illumination applications.

  9. High White Light Photosensitivity of SnSe Nanoplate-Graphene Nanocomposites

    Science.gov (United States)

    Liu, Jinyang; Huang, Qingqing; Zhang, Kun; Xu, Yangyang; Guo, Mingzhu; Qian, Yongqiang; Huang, Zhigao; Lai, Fachun; Lin, Limei

    2017-04-01

    The multi-functional nanomaterial constructed with more than one type of materials has gained a great attention due to its promising application. Here, a high white light photodetector prototype established with two-dimensional material (2D) and 2D nanocomposites has been fabricated. The 2D-2D nanocomposites were synthesized with SnSe nanoplate and graphene. The device shows a linear I-V characterization behavior in the dark and the resistance dramatically decreases under the white light. Furthermore, the photosensitivity of the device is as large as 1110% with a rapid response time, which is much higher than pristine SnSe nanostructure reported. The results shown here may provide a valuable guidance to design and fabricate the photodetector based on the 2D-2D nanocomposites even beyond the SnSe nanoplate-graphene nanocomposites.

  10. Light-Triggered CO2 Breathing Foam via Nonsurfactant High Internal Phase Emulsion.

    Science.gov (United States)

    Zhang, Shiming; Wang, Dingguan; Pan, Qianhao; Gui, Qinyuan; Liao, Shenglong; Wang, Yapei

    2017-10-04

    Solid materials for CO2 capture and storage have attracted enormous attention for gaseous separation, environmental protection, and climate governance. However, their preparation and recovery meet the problems of high energy and financial cost. Herein, a controllable CO2 capture and storage process is accomplished in an emulsion-templated polymer foam, in which CO2 is breathed-in under dark and breathed-out under light illumination. Such a process is likely to become a relay of natural CO2 capture by plants that on the contrary breathe out CO2 at night. Recyclable CO2 capture at room temperature and release under light irradiation guarantee its convenient and cost-effective regeneration in industry. Furthermore, CO2 mixed with CH4 is successfully separated through this reversible breathing in and out system, which offers great promise for CO2 enrichment and practical methane purification.

  11. Manufacturing polymer light emitting diode with high luminance efficiency by solution process

    Science.gov (United States)

    Kim, Miyoung; Jo, SongJin; Yang, Ho Chang; Yoon, Dang Mo; Kwon, Jae-Taek; Lee, Seung-Hyun; Choi, Ju Hwan; Lee, Bum-Joo; Shin, Jin-Koog

    2012-06-01

    While investigating polymer light emitting diodes (polymer-LEDs) fabricated by solution process, surface roughness influences electro-optical (E-O) characteristics. We expect that E-O characteristics such as luminance and power efficiency related to surface roughness and layer thickness of emitting layer with poly-9-Vinylcarbazole. In this study, we fabricated polymer organic light emitting diodes by solution process which guarantees easy, eco-friendly and low cost manufacturing for flexible display applications. In order to obtain high luminescence efficiency, E-O characteristics of these devices by varying parameters for printing process have been investigated. Therefore, we optimized process condition for polymer-LEDs by adjusting annealing temperatures of emission, thickness of emission layer showing efficiency (10.8 cd/A) at 10 mA/cm2. We also checked wavelength dependent electroluminescence spectrum in order to find the correlation between the variation of efficiency and the thickness of the layer.

  12. Aberration production using a high-resolution liquid-crystal spatial light modulator.

    Science.gov (United States)

    Schmidt, Jason D; Goda, Matthew E; Duncan, Bradley D

    2007-05-01

    Phase-only liquid-crystal spatial light modulators provide a powerful means of wavefront control. With high resolution and diffractive (modulo 2pi) operation, they can accurately represent large-dynamic-range phase maps. As a result, they provide an excellent means of producing electrically controllable, dynamic, and repeatable aberrations. However, proper calibration is critical to achieving accurate phase maps. Several calibration methods from previous literature were considered. With simplicity and accuracy in mind, we selected one method for each type of necessary calibration. We augmented one of the selected methods with a new step that improves its accuracy. After calibrating our spatial light modulator with our preferred methods, we evaluated its ability to produce aberrations in the laboratory. We studied Zernike polynomial aberrations using interferometry and Fourier-transform-plane images, and atmospheric aberrations using a Shack-Hartmann wavefront sensor. These measurements show the closest agreement with theoretical expectations that we have seen to date.

  13. General approach to high power, coherent visible and ultraviolet light sources

    DEFF Research Database (Denmark)

    Andersen, Martin Thalbitzer

    -doped GdCOB crystals. The crystals are optimized for noncritical phasematching in the blue-UV spectral region through co-doping with Lu and Sc, a nonlinear coefficient for these crystals of 0.78, 0.81 and 0.89 pm/V are measured, which is comparable to LBO. The ability to adjust the noncritical......The main goal of this project is to develop a generic approach to synthesise any wavelength in the visible and UV spectral region based on sum frequency generation. The approach is based on a hybrid system combining solid state and semiconductor technology. The generation of light in the UV...... phasematching by co-doping of these crystals makes them promising candidates for generation of light in the blue-UV region. A novel method for cavity dumping based on nonlinear frequency conversion is investigated. A high finesse laser is constructed with an intracavity nonlinear material inserted in a beam...

  14. Powerful DMD-based light sources with a high throughput virtual slit

    Science.gov (United States)

    Hajian, Arsen R.; Gooding, Ed; Gunn, Thomas; Bradbury, Steven

    2016-02-01

    Many DMD-based programmable light sources consist of a white light source and a pair of spectrometers operating in subtractive mode. A DMD between the two spectrometers shapes the delivered spectrum. Since both spectrometers must (1) fit within a small volume, and (2) provide significant spectral resolution, a narrow intermediary slit is required. Another approach is to use a spectrometer designed around a High Throughput Virtual Slit, which enables higher spectral resolution than is achievable with conventional spectroscopy by manipulating the beam profile in pupil space. Conventional imaging spectrograph designs image the entrance slit onto the exit focal plane after dispersing the spectrum. Most often, near 1:1 imaging optics are used in order to optimize both entrance aperture and spectral resolution. This approach limits the spectral resolution to the product of the dispersion and the slit width. Achieving high spectral resolution in a compact instrument necessarily requires a narrow entrance slit, which limits instrumental throughput (étendue). By reshaping the pupil with reflective optics, HTVS-equipped instruments create a tall, narrow image profile at the exit focal plane without altering the NA, typically delivering 5X or better spectral resolution than is achievable with a conventional design. This approach works equally well in DMD-based programmable light sources as in single stage spectrometers. Assuming a 5X improvement in étendue, a 500 W source can be replaced by a 100 W equivalent, creating a cooler, more efficient tunable light source with equal power density over the desired bandwidth without compromising output power.

  15. High tolerance to high-light conditions for the protected species Ariocarpus kotschoubeyanus (Cactaceae)

    OpenAIRE

    Arroyo-P?rez, Erika; Flores, Joel; Gonz?lez-Salvatierra, Claudia; Mat?as-Palafox, Mar?a L.; Jim?nez-Sierra, Cecilia

    2017-01-01

    Abstract We determined the seasonal ecophysiological performance under perennial plants and under high solar radiation for adult individuals from the ?living rock? cactus Ariocarpus kotschoubeyanus, which occurs equally under nurse plants and in open spaces. We evaluated the effective quantum yield of photosystem II (?PSII) and the dissipation of thermal energy [non-photochemical quenching (NPQ)] thorough the year. The maximum apparent electron transport rate (ETRmax) and the saturating photo...

  16. Microscopy with microlens arrays: high throughput, high resolution and light-field imaging.

    Science.gov (United States)

    Orth, Antony; Crozier, Kenneth

    2012-06-04

    We demonstrate highly parallelized fluorescence scanning microscopy using a refractive microlens array. Fluorescent beads and rat femur tissue are imaged over a 5.5 mm x 5.5 mm field of view at a pixel throughput of up to 4 megapixels/s and a resolution of 706 nm. We also demonstrate the ability to extract different perspective views of a pile of microspheres.

  17. The High-Temperature Synthesis of the Nanoscaled White-Light Phosphors Applied in the White-Light LEDs

    Directory of Open Access Journals (Sweden)

    Hao-Ying Lu

    2015-01-01

    Full Text Available The white-light phosphors consisting of Dy3+ doped YPO4 and Dy3+ doped YP1-XVXO4 were prepared by the chemical coprecipitation method. After the 1200°C thermal treatment in the air atmosphere, the white-light phosphors with particle sizes around 90 nm can be obtained. In order to reduce the average particle size of phosphors, the alkaline washing method was applied to the original synthesis process, which reduces the particle sizes to 65 nm. From the PLE spectra, four absorption peaks locating at 325, 352, 366, and 390 nm can be observed in the YPO4-based phosphors. These peaks appear due to the following electron transitions: 6H15/2→4K15/2, 6H15/2→4M15/2+6P7/2, 6H15/2→4I11/2, and 6H15/2→4M19/2. Besides, the emission peaks of wavelengths 484 nm and 576 nm can be observed in the PL spectra. In order to obtain the white-light phosphors, the vanadium ions were applied to substitute the phosphorus ions to compose the YP1-XVXO4 phosphors. From the PL spectra, the strongest PL intensity can be obtained with 30% vanadium ions. As the concentration of vanadium ions increases to 40%, the phosphors with the CIE coordinates locating at the white-light area can be obtained.

  18. High performance near-ultraviolet flip-chip light-emitting diodes with distributed Bragg reflector

    Science.gov (United States)

    Choi, Il-Gyun; Jin, Geun-Mo; Park, Jun-Cheon; Jeon, Soo-Kun; Park, Eun-Hyun

    2015-09-01

    We have fabricated the near-ultraviolet (NUV) flip-chip (FC) light-emitting diodes (LEDs) with the high external quantum efficiency (EQE) using distributed Bragg reflectors (DBRs) and compared with conventional FC-LED using silver (Ag) reflector. Reflectance of Ag is very high (90 ~ 95 %) at visible spectrum region, but sharply decrease at NUV region. Therefore we used DBR composed of two different materials which have high-index contrast, such as TiO2 and SiO2. However, to achieve high-performance NUV flip-chip LEDs, we used Ta2O5 instead of TiO2 that absorbs lights of NUV region. Thus, we have designed a DBR composed of twenty pairs of Ta2O5 and SiO2 using optical coating design software. The DBR designed by our group achieves a reflectance of ~99 % in the NUV region (350 ~ 500 nm), which is much better than Ag reflector. Optical power is higher than the Ag-LED up to 22 % @ 390 nm.

  19. High-density all-optical magnetic recording using a high-NA lens illuminated by circularly polarized pulse lights

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Yaoju [College of Physics and Electronic Information, Wenzhou University, Wenzhou 325035 (China)], E-mail: zhangyaoju@sohu.com; Bai Jianping [School of Physics and Electronic Engineering, Nanyang Normal College, Nanyang 472000 (China)

    2008-10-06

    We propose a method for high-density all-optical magnetic recording. Our analyses, based on the vector diffraction theory, show that owing to the inverse Faraday effect, circularly polarized laser pulses focused by a high numerical aperture (NA) lens can induce a small magnetization domain. For an example, the FWHM of the effective magnetization domain is 0.4646{lambda} when NA=0.85. The magnetization direction is basically perpendicular to the surface of the optic-magneto film within the effective magnetization domain and the switching direction of magnetization can be controlled by the helicity of the incident circularly polarized light. These characteristics are useful to next-generation high-density all-optical magnetic storage.

  20. Towards an optimum silicon heterojunction solar cell configuration for high temperature and high light intensity environment

    KAUST Repository

    Abdallah, Amir

    2017-09-22

    We report on the performance of Silicon Heterojunction (SHJ) solar cell under high operating temperature and varying irradiance conditions typical to desert environment. In order to define the best solar cell configuration that resist high operating temperature conditions, two different intrinsic passivation layers were tested, namely, an intrinsic amorphous silicon a-SiO:H with CO/SiH ratio of 0.4 and a-SiOx:H with CO/SiH ratio of 0.8, and the obtained performance were compared with those of a standard SHJ cell configuration having a-Si:H passivation layer. Our results showed how the short circuit current density J, and fill factor FF temperature-dependency are impacted by the cell\\'s configuration. While the short circuit current density J for cells with a-SiO:H layers was found to improve as compared with that of standard a-Si:H layer, introducing the intrinsic amorphous silicon oxide (a-SiO:H) layer with CO/SiH ratio of 0.8 has resulted in a reduction of the FF at room temperature due to hindering the carrier transport by the band structure. Besides, this FF was found to improve as the temperature increases from 15 to 45°C, thus, a positive FF temperature coefficient.

  1. ZnO PN Junctions for Highly-Efficient, Low-Cost Light Emitting Diodes

    Energy Technology Data Exchange (ETDEWEB)

    David P. Norton; Stephen Pearton; Fan Ren

    2007-09-30

    By 2015, the US Department of Energy has set as a goal the development of advanced solid state lighting technologies that are more energy efficient, longer lasting, and more cost-effective than current technology. One approach that is most attractive is to utilize light-emitting diode technologies. Although III-V compound semiconductors have been the primary focus in pursuing this objective, ZnO-based materials present some distinct advantages that could yield success in meeting this objective. As with the nitrides, ZnO is a direct bandgap semiconductor whose gap energy (3.2 eV) can be tuned from 3.0 to 4 eV with substitution of Mg for higher bandgap, Cd for lower bandgap. ZnO has an exciton binding energy of 60 meV, which is larger than that for the nitrides, indicating that it should be a superior light emitting semiconductor. Furthermore, ZnO thin films can be deposited at temperatures on the order of 400-600 C, which is significantly lower than that for the nitrides and should lead to lower manufacturing costs. It has also been demonstrated that functional ZnO electronic devices can be fabricated on inexpensive substrates, such as glass. Therefore, for the large-area photonic application of solid state lighting, ZnO holds unique potential. A significant impediment to exploiting ZnO in light-emitting applications has been the absence of effective p-type carrier doping. However, the recent realization of acceptor-doped ZnO material overcomes this impediment, opening the door to ZnO light emitting diode development In this project, the synthesis and properties of ZnO-based pn junctions for light emitting diodes was investigated. The focus was on three issues most pertinent to realizing a ZnO-based solid state lighting technology, namely (1) achieving high p-type carrier concentrations in epitaxial and polycrystalline films, (2) realizing band edge emission from pn homojunctions, and (3) investigating pn heterojunction constructs that should yield efficient light

  2. High-Throughput Combinatorial Development of High-Entropy Alloys For Light-Weight Structural Applications

    Energy Technology Data Exchange (ETDEWEB)

    Van Duren, Jeroen K; Koch, Carl; Luo, Alan; Sample, Vivek; Sachdev, Anil

    2017-12-29

    The primary limitation of today’s lightweight structural alloys is that specific yield strengths (SYS) higher than 200MPa x cc/g (typical value for titanium alloys) are extremely difficult to achieve. This holds true especially at a cost lower than 5dollars/kg (typical value for magnesium alloys). Recently, high-entropy alloys (HEA) have shown promising SYS, yet the large composition space of HEA makes screening compositions complex and time-consuming. Over the course of this 2-year project we started from 150 billion compositions and reduced the number of potential low-density (<5g/cc), low-cost (<5dollars/kg) high-entropy alloy (LDHEA) candidates that are single-phase, disordered, solid-solution (SPSS) to a few thousand compositions. This was accomplished by means of machine learning to guide design for SPSS LDHEA based on a combination of recursive partitioning, an extensive, experimental HEA database compiled from 24 literature sources, and 91 calculated parameters serving as phenomenological selection rules. Machine learning shows an accuracy of 82% in identifying which compositions of a separate, smaller, experimental HEA database are SPSS HEA. Calculation of Phase Diagrams (CALPHAD) shows an accuracy of 71-77% for the alloys supported by the CALPHAD database, where 30% of the compiled HEA database is not supported by CALPHAD. In addition to machine learning, and CALPHAD, a third tool was developed to aid design of SPSS LDHEA. Phase diagrams were calculated by constructing the Gibbs-free energy convex hull based on easily accessible enthalpy and entropy terms. Surprisingly, accuracy was 78%. Pursuing these LDHEA candidates by high-throughput experimental methods resulted in SPSS LDHEA composed of transition metals (e.g. Cr, Mn, Fe, Ni, Cu) alloyed with Al, yet the high concentration of Al, necessary to bring the mass density below 5.0g/cc, makes these materials hard and brittle, body-centered-cubic (BCC) alloys. A related, yet multi-phase BCC alloy, based

  3. Polymer dots grafted TiO2 nanohybrids as high performance visible light photocatalysts.

    Science.gov (United States)

    Li, Gen; Wang, Feng; Liu, Peng; Chen, Zheming; Lei, Ping; Xu, Zhongshan; Li, Zengxi; Ding, Yanfen; Zhang, Shimin; Yang, Mingshu

    2018-01-18

    As a new member of carbon dots (CDs), Polymer dots (PDs) prepared by hydrothermal treatment of polymers, usually consist of the carbon core and the connected partially degraded polymer chains. This type of CDs might possess aqueous solubility, non-toxicity, excellent stability against photo-bleaching and high visible light activity. In this research, PDs were prepared by a moderate hydrothermal treatment of polyvinyl alcohol, and PDs grafted TiO2 (PDs-TiO2) nanohybrids with TiOC bonds were prepared by a facile in-situ hydrothermal treatment of PDs and Ti (SO4)2. Under visible light irradiation, the PDs-TiO2 demonstrate excellent photocatalytic activity for methyl orange degradation, and the photocatalytic rate constant of PDs-TiO2 is 3.6 and 9.5 times higher than that of pure TiO2 and commercial P25, respectively. In addition, the PDs-TiO2 exhibit good recycle stability under UV-Vis light irradiation. The interfacial TiOC bonds and the π-conjugated structures in PDs-TiO2 can act as the pathways to quickly transfer the excited electrons between PDs and TiO2, therefore contribute to the excellent photocatalytic activity. Copyright © 2018 Elsevier Ltd. All rights reserved.

  4. Highly efficient non-doped blue organic light emitting devices based on anthracene–pyridine derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Haykir, Gulcin; Tekin, Emine; Atalar, Taner; Türksoy, Figen

    2013-12-02

    Four different 2-(10-aryl)anthracen-9-yl)pyridine derivatives 5a–d were synthesized via the Suzuki cross-coupling reaction. Photo-physical characteristics of these materials having strong electron donating or electron withdrawing groups were explored. Multilayer small molecule organic light emitting diodes without any dopant were fabricated in the following sequence: Indium tin oxide/4,4′-bis(N-(1-naphthyl)-N-phenylamino)biphenyl (50 nm)/5a–d (30 nm)/4,7-diphenyl-1,10-phenanthroline (30 nm)/LiF/Al. The electroluminescent property of the device fabricated with 5d as an emitter exhibited a high external quantum efficiency of 3.80% (at around 1 mA/cm{sup 2}) with Commission Internationale De L'Eclairage coordinates of (0.14, 0.25). - Highlights: • Synthesis and characterization of 2-(10-aryl)anthracen-9-yl)pyridine derivatives • Thermal, photophysical and electrochemical properties of anthracene derivatives • Emitters from blue to greenish blue for organic light emitting device applications • Organic light emitting device fabrication and characterization of 2-(10-aryl)anthracen-9-yl)pyridine derivatives.

  5. A high-power fiber-coupled semiconductor light source with low spatio-temporal coherence

    Science.gov (United States)

    Schittko, Robert; Mazurenko, Anton; Tai, M. Eric; Lukin, Alexander; Rispoli, Matthew; Menke, Tim; Kaufman, Adam M.; Greiner, Markus

    2017-04-01

    Interference-induced distortions pose a significant challenge to a variety of experimental techniques, ranging from full-field imaging applications in biological research to the creation of optical potentials in quantum gas microscopy. Here, we present a design of a high-power, fiber-coupled semiconductor light source with low spatio-temporal coherence that bears the potential to reduce the impact of such distortions. The device is based on an array of non-lasing semiconductor emitters mounted on a single chip whose optical output is coupled into a multi-mode fiber. By populating a large number of fiber modes, the low spatial coherence of the input light is further reduced due to the differing optical path lengths amongst the modes and the short coherence length of the light. In addition to theoretical calculations showcasing the feasibility of this approach, we present experimental measurements verifying the low degree of spatial coherence achievable with such a source, including a detailed analysis of the speckle contrast at the fiber end. We acknowledge support from the National Science Foundation, the Gordon and Betty Moore Foundation's EPiQS Initiative, an Air Force Office of Scientific Research MURI program and an Army Research Office MURI program.

  6. Productive common light chain libraries yield diverse panels of high affinity bispecific antibodies

    Science.gov (United States)

    Van Blarcom, Thomas; Melton, Zea; Cheung, Wai Ling; Wagstrom, Chris; McDonough, Dan; Valle Oseguera, Cendy; Ding, Sheng; Rossi, Andrea; Potluri, Shobha; Sundar, Purnima; Sirota, Marina; Yan, Yu; Jones, Jeffrey; Roe-Zurz, Zygy; Srivatsa Srinivasan, Surabhi; Zhai, Wenwu; Pons, Jaume; Rajpal, Arvind; Chaparro-Riggers, Javier

    2018-01-01

    ABSTRACT The commercial success of bispecific antibodies generally has been hindered by the complexities associated with generating appropriate molecules for both research scale and large scale manufacturing purposes. Bispecific IgG (BsIgG) based on two antibodies that use an identical common light chain can be combined with a minimal set of Fc mutations to drive heavy chain heterodimerization in order to address these challenges. However, the facile generation of common light chain antibodies with properties similar to traditional monoclonal antibodies has not been demonstrated and they have only been used sparingly. Here, we describe the design of a synthetic human antibody library based on common light chains to generate antibodies with biochemical and biophysical properties that are indistinguishable to traditional therapeutic monoclonal antibodies. We used this library to generate diverse panels of well-behaved, high affinity antibodies toward a variety of epitopes across multiple antigens, including mouse 4-1BB, a therapeutically important T cell costimulatory receptor. Over 200 BsIgG toward 4-1BB were generated using an automated purification method we developed that enables milligram-scale production of BsIgG. This approach allowed us to identify antibodies with a wide range of agonistic activity that are being used to further investigate the therapeutic potential of antibodies targeting one or more epitopes of 4-1BB. PMID:29227213

  7. Broadband white light emission from Ce:AlN ceramics: High thermal conductivity down-converters for LED and laser-driven solid state lighting

    Directory of Open Access Journals (Sweden)

    A. T. Wieg

    2016-12-01

    Full Text Available We introduce high thermal conductivity aluminum nitride (AlN as a transparent ceramic host for Ce3+, a well-known active ion dopant. We show that the Ce:AlN ceramics have overlapping photoluminescent (PL emission peaks that cover almost the entire visible range resulting in a white appearance under 375 nm excitation without the need for color mixing. The PL is due to a combination of intrinsic AlN defect complexes and Ce3+ electronic transitions. Importantly, the peak intensities can be tuned by varying the Ce concentration and processing parameters, causing different shades of white light without the need for multiple phosphors or light sources. The Commission Internationale de l’Eclairage coordinates calculated from the measured spectra confirm white light emission. In addition, we demonstrate the viability of laser driven white light emission by coupling the Ce:AlN to a readily available frequency tripled Nd-YAG laser emitting at 355 nm. The high thermal conductivity of these ceramic down-converters holds significant promise for producing higher power white light sources than those available today.

  8. Light dark sector searches at low-energy high-luminosity e + e - colliders

    Science.gov (United States)

    Yin, Peng-Fei; Zhu, Shou-Hua

    2016-10-01

    Although the standard model (SM) is extremely successful, there are various motivations for considering the physics beyond the SM. For example, the SM includes neither dark energy nor dark matter, which has been confirmed through astrophysical observations. Examination of the dark sector, which contains new, light, weakly-coupled particles at the GeV scale or lower, is well motivated by both theory and dark-matter detection experiments. In this mini-review, we focus on one particular case in which these new particles can interact with SM particles through a kinematic mixing term between U(1) gauge bosons. The magnitude of the mixing can be parameterized by a parameter є. Following a brief overview of the relevant motivations and the constraints determined from numerous experiments, we focus on the light dark sector phenomenology at low-energy high-luminosity e + e - colliders. These colliders are ideal for probing the new light particles, because of their large production rates and capacity for precise resonance reconstruction. Depending on the details of a given model, the typical observed signatures may also contain multi lepton pairs, displaced vertices, and/or missing energy. Through the use of extremely large data samples from existing experiments, such as KLOE, CLEO, BABAR, Belle, and BESIII, the magnitude of the mixing can be parameterized by a parameter є < 10-4-10-3 constraint can be obtained. Obviously, future experiments with larger datasets will provide opportunities for the discovery of new particles in the dark sector, or for stricter upper limits on є. Once the light dark sector is confirmed, the particle physics landscape will be changed significantly.

  9. Highly luminescent, stable, transparent and flexible perovskite quantum dot gels towards light-emitting diodes

    Science.gov (United States)

    Sun, Chun; Shen, Xinyu; Zhang, Yu; Wang, Yu; Chen, Xingru; Ji, Changyin; Shen, Hongzhi; Shi, Hengchong; Wang, Yiding; Yu, William W.

    2017-09-01

    By controlling the hydrolysis of alkoxysilanes, highly luminescent, transparent and flexible perovskite quantum dot (QD) gels were synthesized. The gels could maintain the structure without shrinking and exhibited excellent stability comparing to the QDs in solution. This in situ fabrication can be easily scaled up for large-area/volume gels. The gels integrated the merits of the polymer matrices to avoid the non-uniformity of light output, making it convenient for practical LED applications. Monochrome and white LEDs were fabricated using these QD gels; the LEDs exhibited broader color gamut, demonstrating better property in the backlight display application.

  10. High flux, narrow bandwidth compton light sources via extended laser-electron interactions

    Science.gov (United States)

    Barty, V P

    2015-01-13

    New configurations of lasers and electron beams efficiently and robustly produce high flux beams of bright, tunable, polarized quasi-monoenergetic x-rays and gamma-rays via laser-Compton scattering. Specifically, the use of long-duration, pulsed lasers and closely-spaced, low-charge and low emittance bunches of electron beams increase the spectral flux of the Compton-scattered x-rays and gamma rays, increase efficiency of the laser-electron interaction and significantly reduce the overall complexity of Compton based light sources.

  11. BESO: first light at the high-resolution spectrograph for the Hexapod-Telescope

    Science.gov (United States)

    Steiner, Ingo; Stahl, Otmar; Seifert, Walter; Chini, Rolf; Quirrenbach, Andreas

    2008-07-01

    BESO (Bochum Echelle Spectrograph for OCA)is a high-resolution echelle spectrograph which has been built by Ruhr-Universitaet, Bochum and Landessternwarte Heidelberg. It is fiber-coupled to the 1.5m Hexapod-Telescope at the Observatario Cerro Armazones (OCA), Chile. The first light spectra show that the resolution of 48.000 over a spectral range from 370 nm to 840 nm has been achieved. An alignment by design approach has been followed to assemble the fiber-head optics at the telescope side of fiber coupled instrument.

  12. Tunable high-refractive index hybrid for solution-processed light management devices (Conference Presentation)

    Science.gov (United States)

    Bachevillier, Stefan

    2016-10-01

    After the use of highly efficient but expensive inorganic optical materials, solution-processable polymers and hybrids have drawn more and more interest. Our group have recently developed a novel polymer-based hybrid optical material from titanium oxide hydrate exhibiting an outstanding set of optical and material properties. Firstly, their low cost, processability and cross-linked states are particularly attractive for many applications. Moreover, a high refractive index can be repeatedly achieved while optical losses stays considerably low over the entire visible and near-infrared wavelength regime. Indeed, the formation of inorganic nanoparticles, usually present in nanocomposites, is avoided by a specific formulation process. Even more remarkably, the refractive index can be tuned by either changing the inorganic content, using different titanium precursors or via a low-temperature curing process. A part of our work is focused on the reliable optical characterization of these properties, in particular a microscope-based setup allowing in-situ measurement and sample mapping has been developed. Our efforts are also concentrated on various applications of these exceptional properties. This hybrid material is tailored for photonic devices, with a specific emphasis on the production of highly efficient solution processable Distributed Bragg Reflectors (DBR) and anti-reflection coatings. Furthermore, waveguides can be fabricated from thin films along with in-coupling and out-coupling structures. These light managements structures are particularly adapted to organic photovoltaic cells (OPVs) and light emitting diodes (OLEDs).

  13. Simple single-emitting layer hybrid white organic light emitting with high color stability

    Science.gov (United States)

    Nguyen, C.; Lu, Z. H.

    2017-10-01

    Simultaneously achieving a high efficiency and color quality at luminance levels required for solid-state lighting has been difficult for white organic light emitting diodes (OLEDs). Single-emitting layer (SEL) white OLEDs, in particular, exhibit a significant tradeoff between efficiency and color stability. Furthermore, despite the simplicity of SEL white OLEDs being its main advantage, the reported device structures are often complicated by the use of multiple blocking layers. In this paper, we report a highly simplified three-layered white OLED that achieves a low turn-on voltage of 2.7 V, an external quantum efficiency of 18.9% and power efficiency of 30 lm/W at 1000 cd/cm2. This simple white OLED also shows good color quality with a color rendering index of 75, CIE coordinates (0.42, 0.46), and little color shifting at high luminance. The device consists of a SEL sandwiched between a hole transport layer and an electron transport layer. The SEL comprises a thermally activated delayer fluorescent molecule having dual functions as a blue emitter and as a host for other lower energy emitters. The improved color stability and efficiency in such a simple device structure is explained as due to the elimination of significant energy barriers at various organic-organic interfaces in the traditional devices having multiple blocking layers.

  14. Highly efficient photocatalytic hydrogen evolution of graphene/YInO3 nanocomposites under visible light irradiation.

    Science.gov (United States)

    Ding, Jianjun; Yan, Wenhao; Xie, Wei; Sun, Song; Bao, Jun; Gao, Chen

    2014-02-21

    Visible-light-driven hydrogen evolution with high efficiency is important in the current photocatalysis research. Here we report for the first time the design and synthesis of a new graphene-semiconductor nanocomposite consisting of YInO3 nanoparticles and two-dimensional graphene sheets as efficient photocatalysts for hydrogen evolution under visible light irradiation. The graphene/YInO3 nanocomposites were synthesized using a facile solvothermal method in which the formation of graphene and the deposition of YInO3 nanoparticles on the graphene sheets can be achieved simultaneously. The addition of graphene as a cocatalyst can narrow the band gap of YInO3 to visible photon energy and prolong the separation and lifetime of electron-hole pairs by the chemical bonding between YInO3 and graphene. The photocatalytic reaction with this nanocomposite reaches a high H2 evolution rate of 400.4 μmol h(-1) g(-1) when the content of graphene is 0.5 wt%, over 127 and 3.7 times higher than that of pure YInO3 and Pt/YInO3, respectively. This work can provide an effective approach to the fabrication of graphene-based photocatalysts with high performance in the field of energy conversion.

  15. High-power light-emitting diode based facility for plant cultivation

    Energy Technology Data Exchange (ETDEWEB)

    Tamulaitis, G [Institute of Materials Science and Applied Research, Vilnius University, Sauletekio al. 9-III, LT-10222 Vilnius (Lithuania); Duchovskis, P [Lithuanian Institute of Horticulture, Babtai, LT-54333 Kaunas District (Lithuania); Bliznikas, Z [Institute of Materials Science and Applied Research, Vilnius University, Sauletekio al. 9-III, LT-10222 Vilnius (Lithuania); Breive, K [Institute of Materials Science and Applied Research, Vilnius University, Sauletekio al. 9-III, LT-10222 Vilnius (Lithuania); Ulinskaite, R [Lithuanian Institute of Horticulture, Babtai, LT-54333 Kaunas District (Lithuania); Brazaityte, A [Lithuanian Institute of Horticulture, Babtai, LT-54333 Kaunas District (Lithuania); Novickovas, A [Institute of Materials Science and Applied Research, Vilnius University, Sauletekio al. 9-III, LT-10222 Vilnius (Lithuania); Zukauskas, A [Institute of Materials Science and Applied Research, Vilnius University, Sauletekio al. 9-III, LT-10222 Vilnius (Lithuania)

    2005-09-07

    Based on perspectives of the development of semiconductor materials systems for high-power light-emitting diodes (LEDs), an illumination facility for greenhouse plant cultivation was designed with the dominating 640 nm photosynthetically active component delivered by AlGaInP LEDs and supplementary components from AlGaN (photothropic action, 455 nm) and AlGaAs (photosynthetic 660 nm and photomorphogenetic 735 nm) LEDs. Photosynthesis intensity, photosynthetic productivity and growth morphology as well as chlorophyll and phytohormone concentrations were investigated in radish and lettuce grown in phytotron chambers under the LED-based illuminators and under high-pressure sodium (HPS) lamps with an equivalent photon flux density. Advantages of the high-power LED-based illuminators over conventional HPS lamps, applicability of AlGaInP LEDs for photosynthesis and control of plant growth by circadian manipulation of a relatively weak far-red component were demonstrated.

  16. Texture analysis integrated to infrared light sources for identifying high fringe concentrations in digital photoelasticity

    Science.gov (United States)

    Fandiño Toro, Hermes; Briñez de León, Juan Carlos; Restrepo Martínez, Alejandro; Branch Bedoya, John W.

    2017-09-01

    In digital photoelasticity images, regions with high fringe densities represent a limitation for unwrapping the phase in specific zones of the stress map. In this work, we recognize such regions by varying the light source wavelength from visible to far infrared, in a simulated experiment based on a circular polariscope observing a birefringent disk under diametral compression. The recognition process involves evaluating the relevance of texture descriptors applied to data sets extracted from regions of interest of the synthetic images, in the visible electromagnetic spectrum and different sub-bands of the infrared. Our results show that extending photoelasticity assemblies to the far infrared, the stress fields could be resolved in regions with high fringe concentrations. Moreover, we show that texture descriptors could overcome limitations associated to the identification of high-stress values in regions in which the fringes are concentrated in the visible spectrum, but not in the infrared.

  17. High brightness phosphorescent organic light emitting diodes on transparent and flexible cellulose films

    Science.gov (United States)

    Purandare, Sumit; Gomez, Eliot F.; Steckl, Andrew J.

    2014-03-01

    Organic light-emitting diodes (OLED) were fabricated on flexible and transparent reconstituted cellulose obtained from wood pulp. Cellulose is naturally available, abundant, and biodegradable and offers a unique substrate alternative for the fabrication of flexible OLEDs. Transparent cellulose material was formed by dissolution of cellulose in an organic solvent (dimethyl acetamide) at elevated temperature (165 °C) in the presence of a salt (LiCl). The optical transmission of 40-μm thick transparent cellulose sheet averaged 85% over the visible spectrum. High brightness and high efficiency thin film OLEDs were fabricated on transparent cellulose films using phosphorescent Ir(ppy)3 as the emitter material. The OLEDs achieved current and luminous emission efficiencies as high as 47 cd A-1 and 20 lm W-1, respectively, and a maximum brightness of 10 000 cd m-2.

  18. Highly efficient tandem organic light-emitting devices employing an easily fabricated charge generation unit

    Science.gov (United States)

    Yang, Huishan; Yu, Yaoyao; Wu, Lishuang; Qu, Biao; Lin, Wenyan; Yu, Ye; Wu, Zhijun; Xie, Wenfa

    2018-02-01

    We have realized highly efficient tandem organic light-emitting devices (OLEDs) employing an easily fabricated charge generation unit (CGU) combining 1,4,5,8,9,11-hexaazatriphenylene-hexacarbonitrile with ultrathin bilayers of CsN3 and Al. The charge generation and separation processes of the CGU have been demonstrated by studying the differences in the current density–voltage characteristics of external-carrier-excluding devices. At high luminances of 1000 and 10000 cd/m2, the current efficiencies of the phosphorescent tandem device are about 2.2- and 2.3-fold those of the corresponding single-unit device, respectively. Simultaneously, an efficient tandem white OLED exhibiting high color stability and warm white emission has also been fabricated.

  19. Investigation of anchor nut loosening in high-mast light poles using field monitoring and finite element analysis.

    Science.gov (United States)

    2014-09-01

    High mast lighting poles (HMLPs) are cost effective structures for lighting highways and intersections. They are 100 to 250 feet (30m to 76m) tall, and can hold a variety of lamp configurations. They are : commonly used at highway interchanges becaus...

  20. High-light acclimation in Quercus robur L.seedlings upon over-topped a shaded environment

    Science.gov (United States)

    Anna M. Jensen; Emile S. Gardiner; Kevin C. Vaughn

    2012-01-01

    High developmental plasticity at the seedling-level during acclimation to the light environment may be an important determinant of seedling establishment and growth in temperate broadleaf forests, especially in dense understories where spatial light availability can vary greatly. Pedunculate oak (Quercus robur L.) seedlings were raised beneath a...

  1. Advanced high-power pulsed light device to decontaminate food from pathogens: effects on Salmonella typhimurium viability in vitro.

    Science.gov (United States)

    Luksiene, Z; Gudelis, V; Buchovec, I; Raudeliuniene, J

    2007-11-01

    The aim of this study was to construct an advanced high-power pulsed light device for decontamination of food matrix and to evaluate its antibacterial efficiency. Key parameters of constructed device-emitted light spectrum, pulse duration, pulse power density, frequency of pulses, dependence of emitted spectrum on input voltage, irradiation homogenicity, possible thermal effects as well as antimicrobial efficiency were evaluated. Antimicrobial efficiency of high-power pulsed light technique was demonstrated and evaluated by two independent methods - spread plate and Miles-Misra method. Viability of Salmonella typhimurium as function of a given light dose (number of pulses) and pulse frequency was examined. According to the data obtained, viability of Salmonella typhimurium reduced by 7 log order after 100 light pulses with power density 133 W cm(-2). In addition, data indicate, that the pulse frequency did not influence the outcome of pathogen inactivation in the region 1-5 Hz. Moreover, no hyperthermic effect was detected during irradiation even after 500 pulses on all shelves with different distance from light source and subsequently different pulse power density (0-252 W cm(-2)). Newly constructed high-power pulsed light technique is effective nonthermal tool for inactivation of Salmonella typhimurium even by 7 log order in vitro. Novel advanced high-power pulsed light device can be a useful tool for development of nonthermal food decontamination technologies.

  2. High-intensity light-emitting diode vs fluorescent tubes for intensive phototherapy in neonates.

    Science.gov (United States)

    Sherbiny, Hanan S; Youssef, Doaa M; Sherbini, Ahmad S; El-Behedy, Rabab; Sherief, Laila M

    2016-05-01

    Special blue fluorescent tubes are recommended by the American Academy of Pediatrics (AAP) as the most effective light source for lowering serum bilirubin. A high-intensity light-emitting diode ('super LED') could render intensive phototherapy more effective than the above conventional methods. This study compared the efficacy and safety of a high-intensity light-emitting diode bed vs conventional intensive phototherapy with triple fluorescent tube units as a rescue treatment for severe unconjugated neonatal hyperbilirubinaemia. This was a randomised, prospective trial. Two hundred jaundiced neonates ≥ 35 weeks gestation who met the criteria for intensive phototherapy as per AAP guidelines were randomly assigned to be treated either with triple fluorescent tube units (group 1, n = 100) or a super LED bed (group 2, n = 100). The outcome was the avoidance of exchange transfusion by successful control of hyperbilirubinaemia. Statistically significant higher success rates of intensive phototherapy were achieved among neonates treated with super LED (group 2) than in those treated conventionally (group 1) (87% vs 64%, P = 0.003). Significantly higher 'bilirubin decline' rates were reported in both haemolytic and non-haemolytic subgroups treated with the super LED bed compared with a similar sub-population in the conventionally treated group. Comparable numbers of neonates in both groups developed rebound jaundice (8% vs 10% of groups 1 and 2, respectively). Side-effects were mild in both groups, but higher rates of hyperthermia (12% vs 0%, P = 0.03), dehydration (8% vs 2%, P = 0.26) and skin rash (39% vs 1%, P = 0.002) were reported in the fluorescent tubes-treated group compared with the LED group. Super LED is a safe rescue treatment for severe neonatal hyperbilirubinaemia, and its implementation may reduce the need for exchange transfusion.

  3. Antioxidant metabolism during acclimation of Begonia x erythrophylla to high light levels.

    Science.gov (United States)

    Burritt, David J; Mackenzie, Susan

    2003-06-01

    This study examined the influence of high light levels on antioxidant metabolism and the photosynthetic properties of Begonia x erythrophylla leaves. The pigment composition of shaded leaves and those developing in full sunlight was typical of shade- and sun-leaves, respectively. After 28 d in full sunlight, the preformed leaves of shade plants transferred to full sunlight (transferred-leaves) showed photo-bleaching with lower Chl (a + b) content and Chl a : Chl b ratios than shade-leaves, with Chl (a + b) : carotenoid ratios not significantly different. The variable/maximal fluorescence (Fv/Fm) of sun-leaves was not significantly different from that of shade-leaves, but transferred-leaves had reduced Fv : Fm ratios. Light response curves for the electron transport rate (ETR), the oxidation state of photosystem II (qP) and non-photochemical quenching (NPQ) showed significant differences between the three leaf types, with transferred-leaves not able to acclimate completely to full sunlight, having lower ETR, qP and NPQ values at high light levels than sun-leaves. Transfer to full sunlight caused a rapid increase in H2O2 and lipid hyperoxides, and a slight increase in protein oxidation. Ascorbate and glutathione levels decreased rapidly, as did the size of the total glutathione pool and, in addition to the general oxidation of proteins, rapid decreases in both the initial and total activities of chloroplastic fructose-1,6-bisphosphatase and glyceraldehyde-3-phosphate dehydrogenase were observed. These results suggest that a more oxidizing cellular environment is the likely cause of the photo-bleaching observed upon transfer of shade-leaves to full sunlight. Acclimation of transferred-leaves to full sunlight involved gradual increases in the activities of enzymes involved in antioxidant metabolism, including superoxide dismutase, catalase, glutathione reductase, ascorbate peroxidase, dehydroascorbate reductase and monodehydroascorbate reductase, but the levels of

  4. High-brightness semipolar (2021¯) blue InGaN/GaN superluminescent diodes for droop-free solid-state lighting and visible-light communications

    KAUST Repository

    Shen, Chao

    2016-05-25

    A high-brightness, droop-free, and speckle-free InGaN/GaN quantum well blue superluminescent diode (SLD) was demonstrated on a semipolar (2021) GaN substrate. The 447-nm emitting SLD has a broad spectral linewidth of 6.3 nm at an optical power of 123 mW. A peak optical power of 256 mW was achieved at 700 mA CW injection current. By combining YAG:Ce phosphor, SLD-generated white light shows a color-rendering index (CRI) of 68.9 and a correlated color temperature (CCT) of 4340 K. The measured frequency response of the SLD revealed a -3 dB bandwidth of 560 MHz, thus demonstrating the feasibility of the device for both solid-state lighting (SSL) and visible-light communication (VLC) applications. © 2016 Optical Society of America.

  5. Graphene–Ag/ZnO nanocomposites as high performance photocatalysts under visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, M., E-mail: mzkhm73@gmail.com [Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan); State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Ahmed, E. [Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan); Hong, Z.L., E-mail: hong_zhanglian@zju.edu.cn [State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Khalid, N.R. [Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan); State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Ahmed, W.; Elhissi, A. [Institute of Nanotechnology and Bioengineering, University of Central Lancashire, School of Medicine and Dentistry, Preston PR1 2HE (United Kingdom)

    2013-11-15

    , great adsorption of dyes, enhanced visible light absorption and fast transfer processes. This research has the potential to provide new avenues for the in situ fabrication of the Graphene–Ag/ZnO composites as highly efficient photocatalysts.

  6. High-precision predictions for the light CP-even Higgs boson mass of the MSSM

    Energy Technology Data Exchange (ETDEWEB)

    Hahn, T.; Hollik, W. [Max-Planck-Institut fuer Physik, Muenchen (Germany); Heinemeyer, S. [Instituto de Fisica de Cantabria (CSIC-UC), Santander (Spain); Rzehak, H. [Freiburg Univ. (Germany). Physikalisches Inst.; Weiglein, G. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2014-03-15

    For the interpretation of the signal discovered in the Higgs searches at the LHC it will be crucial in particular to discriminate between the minimal Higgs sector realised in the Standard Model (SM) and its most commonly studied extension, the Minimal Supersymmetric SM (MSSM). The measured mass value, having already reached the level of a precision observable with an experimental accuracy of about 500 MeV, plays an important role in this context. In the MSSM the mass of the light CP-even Higgs boson, M{sub h}, can directly be predicted from the other parameters of the model. The accuracy of this prediction should at least match the one of the experimental result. The relatively high mass value of about 126 GeV has led to many investigations where the scalar top quarks are in the multi-TeV range. We improve the prediction for M{sub h} in the MSSM by combining the existing fixed-order result, comprising the full one-loop and leading and subleading two-loop corrections, with a resummation of the leading and subleading logarithmic contributions from the scalar top sector to all orders. In this way for the first time a high-precision prediction for the mass of the light CP-even Higgs boson in the MSSM is possible all the way up to the multi-TeV region of the relevant supersymmetric particles. The results are included in the code FeynHiggs.

  7. High-Throughput Light Sheet Microscopy for the Automated Live Imaging of Larval Zebrafish

    Science.gov (United States)

    Baker, Ryan; Logan, Savannah; Dudley, Christopher; Parthasarathy, Raghuveer

    The zebrafish is a model organism with a variety of useful properties; it is small and optically transparent, it reproduces quickly, it is a vertebrate, and there are a large variety of transgenic animals available. Because of these properties, the zebrafish is well suited to study using a variety of optical technologies including light sheet fluorescence microscopy (LSFM), which provides high-resolution three-dimensional imaging over large fields of view. Research progress, however, is often not limited by optical techniques but instead by the number of samples one can examine over the course of an experiment, which in the case of light sheet imaging has so far been severely limited. Here we present an integrated fluidic circuit and microscope which provides rapid, automated imaging of zebrafish using several imaging modes, including LSFM, Hyperspectral Imaging, and Differential Interference Contrast Microscopy. Using this system, we show that we can increase our imaging throughput by a factor of 10 compared to previous techniques. We also show preliminary results visualizing zebrafish immune response, which is sensitive to gut microbiota composition, and which shows a strong variability between individuals that highlights the utility of high throughput imaging. National Science Foundation, Award No. DBI-1427957.

  8. Parallel optical control of spatiotemporal neuronal spike activity using high-frequency digital light processingtechnology

    Directory of Open Access Journals (Sweden)

    Jason eJerome

    2011-08-01

    Full Text Available Neurons in the mammalian neocortex receive inputs from and communicate back to thousands of other neurons, creating complex spatiotemporal activity patterns. The experimental investigation of these parallel dynamic interactions has been limited due to the technical challenges of monitoring or manipulating neuronal activity at that level of complexity. Here we describe a new massively parallel photostimulation system that can be used to control action potential firing in in vitro brain slices with high spatial and temporal resolution while performing extracellular or intracellular electrophysiological measurements. The system uses Digital-Light-Processing (DLP technology to generate 2-dimensional (2D stimulus patterns with >780,000 independently controlled photostimulation sites that operate at high spatial (5.4 µm and temporal (>13kHz resolution. Light is projected through the quartz-glass bottom of the perfusion chamber providing access to a large area (2.76 x 2.07 mm2 of the slice preparation. This system has the unique capability to induce temporally precise action potential firing in large groups of neurons distributed over a wide area covering several cortical columns. Parallel photostimulation opens up new opportunities for the in vitro experimental investigation of spatiotemporal neuronal interactions at a broad range of anatomical scales.

  9. Visible light photooxidative performance of a high-nuclearity molecular bismuth vanadium oxide cluster

    Directory of Open Access Journals (Sweden)

    Johannes Tucher

    2014-05-01

    Full Text Available The visible light photooxidative performance of a new high-nuclearity molecular bismuth vanadium oxide cluster, H3[{Bi(dmso3}4V13O40], is reported. Photocatalytic activity studies show faster reaction kinetics under anaerobic conditions, suggesting an oxygen-dependent quenching of the photoexcited cluster species. Further mechanistic analysis shows that the reaction proceeds via the intermediate formation of hydroxyl radicals which act as oxidant. Trapping experiments using ethanol as a hydroxyl radical scavenger show significantly decreased photocatalytic substrate oxidation in the presence of EtOH. Photocatalytic performance analyses using monochromatic visible light irradiation show that the quantum efficiency Φ for indigo photooxidation is strongly dependent on the irradiation wavelength, with higher quantum efficiencies being observed at shorter wavelengths (Φ395nm ca. 15%. Recycling tests show that the compound can be employed as homogeneous photooxidation catalyst multiple times without loss of catalytic activity. High turnover numbers (TON ca. 1200 and turnover frequencies up to TOF ca. 3.44 min−1 are observed, illustrating the practical applicability of the cluster species.

  10. The effect of high frequency sound on Culicoides numbers collected with suction light traps

    Directory of Open Access Journals (Sweden)

    Gert J. Venter

    2012-04-01

    Full Text Available Culicoides midges (Diptera: Ceratopogonidae, are involved in the transmission of various pathogens that cause important diseases of livestock worldwide. The use of insect repellents to reduce the attack rate of these insects on livestock could play an important role as part of an integrated control programme against diseases transmitted by these midges. The objective of this study was to determine whether high frequency sound has any repellent effect on Culicoides midges. The number of midges collected with 220 V Onderstepoort white light traps fitted with electronic mosquito repellents (EMRs, emitting 5-20 KHz multi-frequency sound waves, was compared with that of two untreated traps. Treatments were rotated in two replicates of a 4 x 4 randomised Latin square design. Although fewer midges were collected in the two traps fitted with EMRs, the average number collected over eight consecutive nights was not significantly different. The EMRs also had no influence on any of the physiological groups of Culicoides imicola Kieffer or the species composition of the Culicoides population as determined with light traps. The results indicate that high frequency sound has no repellent effect on Culicoides midges. There is therefore no evidence to support their promotion or use in the protection of animals against pathogens transmitted by Culicoides midges.

  11. High optical bandwidth GaN based photonic-crystal light-emitting diodes

    Science.gov (United States)

    Lin, Tung-Ching; Yin, Yu-Feng; Lan, Wen-Yi; Huang, JianJang

    2016-09-01

    Light emitting diodes (LEDs) for visible light communication (VLC) as radio sources is a solution to channel crowding of radio frequency (RF) signal. However, for the application on high-speed communication, getting higher bandwidth of LEDs is always the problem which is limited by the spontaneous carrier lifetime in the multiple quantum wells. In this paper, we proposed GaN-based LEDs accompanied with photonic crystal (PhC) nanostructure for high speed communication. Using the characteristic of photonic band selection in photonic crystal structure, the guided modes are modulated by RF signal. The PhC can also provide faster mode extraction. From time resolved photoluminescence (TRPL) at room temperature, carrier lifetime of both lower- and higher-order modes is shortened. By observing f-3dB -J curve, it reveals that the bandwidth of PhC LEDs is higher than that of typical LED. The optical - 3-dB bandwidth (f-3dB) can be achieved up to 240 MHz in the PhC LED (PhCLED). We conclude that the higher operation speed can be obtained due to faster radiative carrier recombination of extracted guided modes from the PhC nanostructure.

  12. Parallel optical control of spatiotemporal neuronal spike activity using high-speed digital light processing.

    Science.gov (United States)

    Jerome, Jason; Foehring, Robert C; Armstrong, William E; Spain, William J; Heck, Detlef H

    2011-01-01

    Neurons in the mammalian neocortex receive inputs from and communicate back to thousands of other neurons, creating complex spatiotemporal activity patterns. The experimental investigation of these parallel dynamic interactions has been limited due to the technical challenges of monitoring or manipulating neuronal activity at that level of complexity. Here we describe a new massively parallel photostimulation system that can be used to control action potential firing in in vitro brain slices with high spatial and temporal resolution while performing extracellular or intracellular electrophysiological measurements. The system uses digital light processing technology to generate 2-dimensional (2D) stimulus patterns with >780,000 independently controlled photostimulation sites that operate at high spatial (5.4 μm) and temporal (>13 kHz) resolution. Light is projected through the quartz-glass bottom of the perfusion chamber providing access to a large area (2.76 mm × 2.07 mm) of the slice preparation. This system has the unique capability to induce temporally precise action potential firing in large groups of neurons distributed over a wide area covering several cortical columns. Parallel photostimulation opens up new opportunities for the in vitro experimental investigation of spatiotemporal neuronal interactions at a broad range of anatomical scales.

  13. High Performance Metal Halide Perovskite Light-Emitting Diode: From Material Design to Device Optimization.

    Science.gov (United States)

    Shan, Qingsong; Song, Jizhong; Zou, Yousheng; Li, Jianhai; Xu, Leimeng; Xue, Jie; Dong, Yuhui; Han, Boning; Chen, Jiawei; Zeng, Haibo

    2017-12-01

    Metal halide perovskites have drawn significant interest in the past decade. Superior optoelectronic properties, such as a narrow bandwidth, precise and facile tunable luminance over the entire visible spectrum, and high photoluminescence quantum yield of up to ≈100%, render metal halide perovskites suitable for next-generation high-definition displays and healthy lighting systems. The external quantum efficiency of perovskite light-emitting diodes (LEDs) increases from 0.1 to 11.7% in three years; however, the energy conversion efficiency and the long-term stability of perovskite LEDs are inadequate for practical application. Strategies to optimize the emitting layer and the device structure, with respect to material design, synthesis, surface passivation, and device optimization, are reviewed and highlighted. The long-term stability of perovskite LEDs is evaluated as well. Meanwhile, several challenges and prospects for future development of perovskite materials and LEDs are identified. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Sliding Mode Pulsed Averaging IC Drivers for High Brightness Light Emitting Diodes

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Anatoly Shteynberg, PhD

    2006-08-17

    This project developed new Light Emitting Diode (LED) driver ICs associated with specific (uniquely operated) switching power supplies that optimize performance for High Brightness LEDs (HB-LEDs). The drivers utilize a digital control core with a newly developed nonlinear, hysteretic/sliding mode controller with mixed-signal processing. The drivers are flexible enough to allow both traditional microprocessor interface as well as other options such as “on the fly” adjustment of color and brightness. Some other unique features of the newly developed drivers include • AC Power Factor Correction; • High power efficiency; • Substantially fewer external components should be required, leading to substantial reduction of Bill of Materials (BOM). Thus, the LED drivers developed in this research : optimize LED performance by increasing power efficiency and power factor. Perhaps more remarkably, the LED drivers provide this improved performance at substantially reduced costs compared to the present LED power electronic driver circuits. Since one of the barriers to market penetration for HB-LEDs (in particular “white” light LEDs) is cost/lumen, this research makes important contributions in helping the advancement of SSL consumer acceptance and usage.

  15. High-Performance Red-Light Photodetector Based on Lead-Free Bismuth Halide Perovskite Film.

    Science.gov (United States)

    Tong, Xiao-Wei; Kong, Wei-Yu; Wang, You-Yi; Zhu, Jin-Miao; Luo, Lin-Bao; Wang, Zheng-Hua

    2017-06-07

    In this study, we developed a sensitive red-light photodetector (RLPD) based on CsBi3I10 perovskite thin film. This inorganic, lead-free perovskite was fabricated by a simple spin-coating method. Device analysis reveals that the as-assembled RLPD was very sensitive to 650 nm light, with an on/off ratio as high as 10(5). The responsivity and specific detectivity of the device were estimated to be 21.8 A/W and 1.93 × 10(13) Jones, respectively, which are much better than those of other lead halide perovskite devices. In addition, the device shows a fast response (rise time: 0.33 ms; fall time: 0.38 ms) and a high external quantum efficiency (4.13 × 10(3)%). It is also revealed that the RLPD has a very good device stability even after storage for 3 months under ambient conditions. In summary, we suggest that the CsBi3I10 perovskite photodetector developed in this study may have potential applications in future optoelectronic systems.

  16. 4 Gbps direct modulation of 450 nm GaN laser for high-speed visible light communication.

    Science.gov (United States)

    Lee, Changmin; Zhang, Chong; Cantore, Michael; Farrell, Robert M; Oh, Sang Ho; Margalith, Tal; Speck, James S; Nakamura, Shuji; Bowers, John E; DenBaars, Steven P

    2015-06-15

    We demonstrate high-speed data transmission with a commercial high power GaN laser diode at 450 nm. 2.6 GHz bandwidth was achieved at an injection current of 500 mA using a high-speed visible light communication setup. Record high 4 Gbps free-space data transmission rate was achieved at room temperature.

  17. 4 Gbps direct modulation of 450 nm GaN laser for high-speed visible light communication

    KAUST Repository

    Lee, Changmin

    2015-06-10

    We demonstrate high-speed data transmission with a commercial high power GaN laser diode at 450 nm. 2.6 GHz bandwidth was achieved at an injection current of 500 mA using a high-speed visible light communication setup. Record high 4 Gbps free-space data transmission rate was achieved at room temperature.

  18. A High-Precision Registration Technology Based on Bundle Adjustment in Structured Light Scanning System

    Directory of Open Access Journals (Sweden)

    Jianying Yuan

    2014-01-01

    Full Text Available The multiview 3D data registration precision will decrease with the increasing number of registrations when measuring a large scale object using structured light scanning. In this paper, we propose a high-precision registration method based on multiple view geometry theory in order to solve this problem. First, a multiview network is constructed during the scanning process. The bundle adjustment method from digital close range photogrammetry is used to optimize the multiview network to obtain high-precision global control points. After that, the 3D data under each local coordinate of each scan are registered with the global control points. The method overcomes the error accumulation in the traditional registration process and reduces the time consumption of the following 3D data global optimization. The multiview 3D scan registration precision and efficiency are increased. Experiments verify the effectiveness of the proposed algorithm.

  19. High-density G-centers, light-emitting point defects in silicon crystal

    Directory of Open Access Journals (Sweden)

    Koichi Murata

    2011-09-01

    Full Text Available We propose a new method of creating light-emitting point defects, or G-centers, by modifying a silicon surface with hexamethyldisilazane followed by laser annealing of the surface region. This laser annealing process has two advantages: creation of highly dense G-centers by incorporating carbon atoms into the silicon during heating; freezing in the created G-centers during rapid cooling. The method provides a surface region of up to 200 nm with highly dense carbon atoms of up to 4 × 1019 cm−3 to create G-centers, above the solubility limit of carbon atoms in silicon crystal (3 × 1017 cm−3. Photoluminescence measurement reveals that the higher-speed laser annealing produces stronger G-center luminescence. We demonstrate electrically-driven emission from the G-centers in samples made using our new method.

  20. High-quality vertical light emitting diodes fabrication by mechanical lift-off technique

    Science.gov (United States)

    Tu, Po-Min; Hsu, Shih-Chieh; Chang, Chun-Yen

    2011-10-01

    We report the fabrication of mechanical lift-off high quality thin GaN with Hexagonal Inversed Pyramid (HIP) structures for vertical light emitting diodes (V-LEDs). The HIP structures were formed at the GaN/sapphire substrate interface under high temperature during KOH wet etching process. The average threading dislocation density (TDD) was estimated by transmission electron microscopy (TEM) and found the reduction from 2×109 to 1×108 cm-2. Raman spectroscopy analysis revealed that the compressive stress of GaN epilayer was effectively relieved in the thin-GaN LED with HIP structures. Finally, the mechanical lift-off process is claimed to be successful by using the HIP structures as a sacrificial layer during wafer bonding process.

  1. In silico evaluation of highly efficient organic light-emitting materials

    Science.gov (United States)

    Kwak, H. Shaun; Giesen, David J.; Hughes, Thomas F.; Goldberg, Alexander; Cao, Yixiang; Gavartin, Jacob; Dixon, Steve; Halls, Mathew D.

    2016-09-01

    Design and development of highly efficient organic and organometallic dopants is one of the central challenges in the organic light-emitting diodes (OLEDs) technology. Recent advances in the computational materials science have made it possible to apply computer-aided evaluation and screening framework directly to the design space of organic lightemitting diodes (OLEDs). In this work, we will showcase two major components of the latest in silico framework for development of organometallic phosphorescent dopants - (1) rapid screening of dopants by machine-learned quantum mechanical models and (2) phosphorescence lifetime predictions with spin-orbit coupled calculations (SOC-TDDFT). The combined work of virtual screening and evaluation would significantly widen the design space for highly efficient phosphorescent dopants with unbiased measures to evaluate performance of the materials from first principles.

  2. High Precision Stokes Polarimetry for Scattering Light using Wide Dynamic Range Intensity Detector

    Directory of Open Access Journals (Sweden)

    Shibata Shuhei

    2015-01-01

    Full Text Available This paper proposes a Stokes polarimetry for scattering light from a sample surface. To achieve a high accuracy measurement two approaches of an intensity detector and analysis algorism of a Stokes parameter were proposed. The dynamic range of this detector can achieve up to 1010 by combination of change of neutral-density (ND filters having different density and photon counting units. Stokes parameters can be measured by dual rotating of a retarder and an analyzer. The algorism of dual rotating polarimeter can be calibrated small linear diattenuation and linear retardance error of the retarder. This system can measured Stokes parameters from −20° to 70° of its scattering angle. It is possible to measure Stokes parameters of scattering of dust and scratch of optical device with high precision. This paper shows accuracy of this system, checking the polarization change of scattering angle and influence of beam size.

  3. Modular sub-wavelength diffractive light modulator for high-definition holographic displays

    Science.gov (United States)

    Stahl, Richard; Rochus, Veronique; Rottenberg, Xavier; Cosemans, Stefan; Haspeslagh, Luc; Severi, Simone; Van der Plas, Geert; Lafruit, Gauthier; Donnay, Stephane

    2013-02-01

    Holography is undoubtedly the ultimate 3D visualization technology, offering true 3D experience with all the natural depth cues, without the undesirable side-effects of current stereoscopic systems (uncomfortable glasses, strained eyes, fatiguing experience). Realization of a high-definition holographic display however requires a number of breakthroughs from existing prototypes. One of the main challenges lies in technology scaling, as holography is based on light diffraction and interference - to achieve wide viewing angles, the light-modulating pixels need to be spaced close to or below the wavelength of the used visible light. Furthermore, achieving high 3D image quality, hundreds of millions of such individually programmable pixels are needed. As a solution, we develop a modular sub-wavelength light modulator, consisting of three main sub-systems: the optical sub-system, comprising a 2D array of sub-wavelength pixels; the driver sub-system for individual pixel control, and the holographic computational engine. Based on conclusions from our state-of-the art studies, numerous experiments and holographic demonstrators, we have focused on reflective phase-modulating MEMS-based system and its scaling beyond 500nm pitch. We have devised a unique binary-programmable phase-modulating pixel architecture realizing vertical pixel displacement of up to 150nm at 500nm by 500nm pixel pitch, while sustaining low operating voltages compatible with CMOS driver circuitry. IMEC SiGe MEMS technology enables integration of the CMOS pixel-line drivers, scan-line drivers and I/O circuits underneath the 2D MEMS array, resulting in a compact and modular single-chip system design. Refresh rates of few hundred frames per second are achieved using our patented segmented driver-array architecture. Integrated circuits implementing parallel holographic computational engines can be added to the module using advanced 3D stacking technology. Herein we further report on our progress in realizing

  4. Role of light satellites in the high-resolution Earth observation domain

    Science.gov (United States)

    Fishman, Moshe

    1999-12-01

    Current 'classic' applications using and exploring space based earth imagery are exclusive, narrow niche tailored, expensive and hardly accessible. On the other side new, inexpensive and widely used 'consumable' applications will be only developed concurrently to the availability of appropriate imagery allowing that process. A part of these applications can be imagined today, like WWW based 'virtual tourism' or news media, but the history of technological, cultural and entertainment evolution teaches us that most of future applications are unpredictable -- they emerge together with the platforms enabling their appearance. The only thing, which can be ultimately stated, is that the definitive condition for such applications is the availability of the proper imagery platform providing low cost, high resolution, large area, quick response, simple accessibility and quick dissemination of the raw picture. This platform is a constellation of Earth Observation satellites. Up to 1995 the Space Based High Resolution Earth Observation Domain was dominated by heavy, super-expensive and very inflexible birds. The launch of Israeli OFEQ-3 Satellite by MBT Division of Israel Aircraft Industries (IAI) marked the entrance to new era of light, smart and cheap Low Earth Orbited Imaging satellites. The Earth Resource Observation System (EROS) initiated by West Indian Space, is based on OFEQ class Satellites design and it is capable to gather visual data of Earth Surface both at high resolution and large image capacity. The main attributes, derived from its compact design, low weight and sophisticated logic and which convert the EROS Satellite to valuable and productive system, are discussed. The major advantages of Light Satellites in High Resolution Earth Observation Domain are presented and WIS guidelines featuring the next generation of LEO Imaging Systems are included.

  5. Cu ion ink for a flexible substrate and highly conductive patterning by intensive pulsed light sintering.

    Science.gov (United States)

    Wang, Byung-Yong; Yoo, Tae-Hee; Song, Yong-Won; Lim, Dae-Soon; Oh, Young-Jei

    2013-05-22

    Direct printing techniques that utilize nanoparticles to mitigate environmental pollution and reduce the processing time of the routing and formation of electrodes have received much attention lately. In particular, copper (Cu) nanoink using Cu nanoparticles offers high conductivity and can be prepared at low cost. However, it is difficult to produce homogeneous nanoparticles and ensure good dispersion within the ink. Moreover, Cu particles require a sintering process over an extended time at a high temperature due to high melting temperature of Cu. During this process, the nanoparticles oxidize quickly in air. To address these problems, the authors developed a Cu ion ink that is free of Cu particles or any other impurities. It consequently does not require separate dispersion stability. In addition, the developed ink is environmentally friendly and can be sintered even at low temperatures. The Cu ion ink was sintered on a flexible substrate using intense pulsed light (IPL), which facilitates large-area, high-speed calcination at room temperature and at atmospheric pressures. As the applied light energy increases, the Cu2O phase diminishes, leaving only the Cu phase. This is attributed to the influence of formic acid (HCOOH) on the Cu ion ink. Only the Cu phase was observed above 40 J cm(-2). The Cu-patterned film after sintering showed outstanding electrical resistivity in a range of 3.21-5.27 μΩ·cm at an IPL energy of 40-60 J cm(-2). A spiral-type micropattern with a line width of 160 μm on a PI substrate was formed without line bulges or coffee ring effects. The electrical resistivity was 5.27 μΩ·cm at an energy level of 40.6 J cm(-2).

  6. Highly Effective Light Beam Diffraction on Holographic PDLC Photonic Structure, Controllable by the Spatially Inhomogeneous Electric Field

    Science.gov (United States)

    Semkin, A. O.; Sharangovich, S. N.

    In this work the highly effiective light beam diffraction on holographic photonic structure formed in polymer-dispersed liquid crystal (PDLCs) is theoretically described. The ability to manage its diffraction characteristics by the spatially inhomogeneous electric field is also shown.

  7. Wearable red-green-blue quantum dot light-emitting diode array using high-resolution intaglio transfer printing

    National Research Council Canada - National Science Library

    Choi, Moon Kee; Yang, Jiwoong; Kang, Kwanghun; Kim, Dong Chan; Choi, Changsoon; Park, Chaneui; Kim, Seok Joo; Chae, Sue In; Kim, Tae-Ho; Kim, Ji Hoon; Hyeon, Taeghwan; Kim, Dae-Hyeong

    2015-01-01

    Deformable full-colour light-emitting diodes with ultrafine pixels are essential for wearable electronics, which requires the conformal integration on curvilinear surface as well as retina-like high-definition displays...

  8. The measurements of light high-energy ions in NINA-2 experiment

    Directory of Open Access Journals (Sweden)

    A. Leonov

    2007-10-01

    Full Text Available The flux of energetic light ions at low altitude is both an important input and output for self-consistent calculations of albedo particles resulting from the interaction of trapped and cosmic ray particles, with the upper atmosphere. In addition, data on the flux of light ions are needed to evaluate radiation damages on space-borne instruments and on space mission crews. In spite of that, sources of data on the flux of energetic ions at LEO are roughly limited to the AP-8 model, CREME/CREME96 codes and the SAMPEX, NOAA/TIROS satellites. The existing and operational European SAC-C/ICARE and PROBA-1/SREM instruments could also be potential sources for proton data at LEO. Although AP-8 and SAMPEX/PSB97 may be publicly accessed through the SPENVIS, they exhibit an order of magnitude difference in low altitude proton fluxes and they do not contain helium fluxes. Therefore, improved light ion radiation models are still needed.

    In this paper we present a procedure to identify and measure the energy of ions that are not stopped in the NINA-2 instrument. Moreover, problems related to particles that cross the instrument in the opposite direction are addressed and shown to be a possible cause of particle misidentification. Measuring fluxes of low abundance elements like energetic helium ions requires a good characterisation of all possible sources of backgrounds in the detector. Hints to determine the several contributions to the background are presented herein and may be applied to extract an order of magnitude of energetic ions fluxes from existing data sets, while waiting for dedicated high performance instruments.

  9. Conventional and high-intensity halogen light effects on polymerization shrinkage of orthodontic adhesives.

    Science.gov (United States)

    Sener, Yagmur; Uysal, Tancan; Basciftci, Faruk Ayhan; Demir, Abdullah; Botsali, Murat Selim

    2006-07-01

    The objectives of this study were to compare the polymerization shrinkage of three orthodontic adhesives. In addition we wanted to determine the effectiveness of the high-intensity quartz tungsten halogen (HQTH) in curing orthodontic adhesives on polymerization shrinkage with that of the quartz tungsten halogen (QTH). A total of 120 glass ring molds were prepared using a low-speed saw. The internal surface of the glass rings were roughened and etched. Adhesive pastes were placed into the glass molds, which were sandwiched between two glass slides. Samples were divided into six groups according to the combination of three orthodontic adhesives (Kurasper F, Light Bond, and Transbond XT) and two light intensities. One half of each 40 samples of three adhesive pastes was polymerized for 20 seconds by a QTH (Hilux 350), and the other half was polymerized for 10 seconds by a HQTH (Optilux 501). The volumetric polymerization shrinkage for each system was measured through the specific density method modified by Puckett and Smith. Statistical analysis was performed using two-way analysis of variance for intergroup comparisons. The HQTH-curing unit resulted in a more polymerization shrinkage than did the QTH for all investigated adhesives. However, no statistically significant differences were found. The highest shrinkage was observed for Light Bond cured with HQTH (1.59 +/- 0.82%), and the lowest value was observed for Transbond XT cured with QTH (1.23 +/- 0.60%). There are no significant differences in polymerization shrinkage of the three investigated orthodontic adhesives when polymerized with a QTH or a HQTH.

  10. High-speed polarized light microscopy for in situ, dynamic measurement of birefringence properties

    Science.gov (United States)

    Wu, Xianyu; Pankow, Mark; Shadow Huang, Hsiao-Ying; Peters, Kara

    2018-01-01

    A high-speed, quantitative polarized light microscopy (QPLM) instrument has been developed to monitor the optical slow axis spatial realignment during controlled medium to high strain rate experiments at acquisition rates up to 10 kHz. This high-speed QPLM instrument is implemented within a modified drop tower and demonstrated using polycarbonate specimens. By utilizing a rotating quarter wave plate and a high-speed camera, the minimum acquisition time to generate an alignment map of a birefringent specimen is 6.1 ms. A sequential analysis method allows the QPLM instrument to generate QPLM data at the high-speed camera imaging frequency 10 kHz. The obtained QPLM data is processed using a vector correlation technique to detect anomalous optical axis realignment and retardation changes throughout the loading event. The detected anomalous optical axis realignment is shown to be associated with crack initiation, propagation, and specimen failure in a dynamically loaded polycarbonate specimen. The work provides a foundation for detecting damage in biological tissues through local collagen fiber realignment and fracture during dynamic loading.

  11. Design of a lighting system with high-power LEDs, large area electronics, and light management structure in the LUMENTILE European project

    Science.gov (United States)

    Carraro, L.; Simonetta, M.; Benetti, G.; Tramonte, A.; Capelli, G.; Benedetti, M.; Randone, E. M.; Ylisaukko-oja, A.; Keränen, K.; Facchinetti, T.; Giuliani, G.

    2017-02-01

    LUMENTILE (LUMinous ElectroNic TILE) is a project funded by the European Commission with the goal of developing a luminous tile with novel functionalities, capable of changing its color and interact with the user. Applications include interior/exterior tile for walls and floors covering, high-efficiency luminaries, and advertising under the form of giant video screens. High overall electrical efficiency of the tile is mandatory, as several millions of square meters are foreseen to be installed each year. Demand is for high uniformity of the illumination of the top tile surface, and for high optical extraction efficiency. These features are achieved by smart light management, using a new approach based on light guiding slab and spatially selective light extraction obtained using both diffusion and/or reflection from the top and bottom interfaces of the optical layer. Planar and edge configurations for the RGB LEDs are considered and compared. A square shape with side length from 20cm to 60cm is considered for the tiles. The electronic circuit layout must optimize the electrical efficiency, and be compatible with low-cost roll-to-roll production on flexible substrates. LED heat management is tackled by using dedicated solutions that allow operation in thermally harsh environment. An approach based on OLEDs has also been considered, still needing improvement on emitted power and ruggedness.

  12. High-performance light-emitting diodes encapsulated with silica-filled epoxy materials.

    Science.gov (United States)

    Li, Tian; Zhang, Jie; Wang, Huiping; Hu, Zhongnan; Yu, Yingfeng

    2013-09-25

    Packaging materials have a great impact on the performance and reliability of light-emitting diodes (LEDs). In this study, we have prepared high performance LED devices through encapsulating LEDs by epoxy materials incorporated with filler powders. A set of evaluation methods have also been established to characterize the reliability of LED devices. No delamination or internal cracking between packaging materials and lead frames has been found for the encapsulated high performance LED devices after the package saturation with moisture and subsequent exposure to high-temperature solder reflow and thermal cycling. Four kinds of inorganic silica fillers, namely, quartz, fused silica, cristobalite, and spherical silica, and one kind of organic filler, that is, spherical silicone powder, were incorporated into the epoxy packaging materials to compare their effects on performance of LED devices. The properties of epoxy packaging materials and LED devices were studied by differential scanning calorimetry (DSC), thermogravimetric analyses (TGA), dynamic mechanical analysis (DMA), thermomechanical analyzer (TMA), ultravioletvisible spectrophotometer (UV-vis), scanning acoustic microscopy (SAM), and scanning electron microscopy (SEM). Except the spherical silicone powder filled epoxy materials, all the other filled systems showed lower equilibrium water sorption content and smaller water diffusion coefficient in both water sorption and moisture sorption tests. The coefficient of thermal expansion (CTE) values were also decreased with the addition of fillers, and the systems filled with quartz, fused, and filled with spherical silica gave the best performance, which exhibited the reduced CTE values both below and above Tg. The results of TGA essentially showed no difference between filled and unfilled systems. The glass transition temperature changed little for all the filled systems, except the one incorporated with spherical silicone. The modulus at room temperature

  13. Solution-processed, high-performance light-emitting diodes based on quantum dots

    Science.gov (United States)

    Dai, Xingliang; Zhang, Zhenxing; Jin, Yizheng; Niu, Yuan; Cao, Hujia; Liang, Xiaoyong; Chen, Liwei; Wang, Jianpu; Peng, Xiaogang

    2014-11-01

    Solution-processed optoelectronic and electronic devices are attractive owing to the potential for low-cost fabrication of large-area devices and the compatibility with lightweight, flexible plastic substrates. Solution-processed light-emitting diodes (LEDs) using conjugated polymers or quantum dots as emitters have attracted great interest over the past two decades. However, the overall performance of solution-processed LEDs--including their efficiency, efficiency roll-off at high current densities, turn-on voltage and lifetime under operational conditions--remains inferior to that of the best vacuum-deposited organic LEDs. Here we report a solution-processed, multilayer quantum-dot-based LED with excellent performance and reproducibility. It exhibits colour-saturated deep-red emission, sub-bandgap turn-on at 1.7 volts, high external quantum efficiencies of up to 20.5 per cent, low efficiency roll-off (up to 15.1 per cent of the external quantum efficiency at 100 mA cm-2), and a long operational lifetime of more than 100,000 hours at 100 cd m-2, making this device the best-performing solution-processed red LED so far, comparable to state-of-the-art vacuum-deposited organic LEDs. This optoelectronic performance is achieved by inserting an insulating layer between the quantum dot layer and the oxide electron-transport layer to optimize charge balance in the device and preserve the superior emissive properties of the quantum dots. We anticipate that our results will be a starting point for further research, leading to high-performance, all-solution-processed quantum-dot-based LEDs ideal for next-generation display and solid-state lighting technologies.

  14. Photoluminescence and reflectivity studies of high energy light ions irradiated polymethyl methacrylate films

    Science.gov (United States)

    Bharti, Madhu Lata; Singh, Fouran; Ramola, R. C.; Joshi, Veena

    2017-11-01

    The self-standing films of non-conducting polymethyl methacrylate (PMMA) were irradiated in vacuum using high energy light ions (HELIs) of 50 MeV Lithium (Li+3) and 80 MeV Carbon (C+5) at various ion dose to induce the optical changes in the films. Upon HELI irradiation, films exhibit a significant enhancement in optical reflectivity at the highest dose. Interestingly, the photoluminescence (PL) emission band with green light at (514.5 nm) shows a noticeable increase in the intensity with increasing ion dose for both ions. However, the rate of increase in PL intensity is different for both HELI and can be correlated with the linear energy transfer by these ions in the films. Origin of PL is attributed to the formation of carbon cluster and hydrogenated amorphous carbon in the polymer films. HAC clusters act as PL active centres with optical reflectivity. Most of the harmful radiation like UV are absorbed by the material and is becoming opaque after irradiation and this PL active material are useful in fabrication of optoelectronic devices, UV-filter, back-lit components in liquid crystal display systems, micro-components for integrate optical circuits, diffractive elements, advanced materials and are also applicable to the post irradiation laser treatment by means of ion irradiation.

  15. Heterostructures of Ag₃PO₄/TiO₂ mesoporous spheres with highly efficient visible light photocatalytic activity.

    Science.gov (United States)

    Li, Yanjuan; Yu, Liangmin; Li, Nan; Yan, Wenfu; Li, Xiaotian

    2015-07-15

    Heterostructured Ag3PO4/m-TiO2 (mesoporous sphere) visible-light photocatalyst has been synthesized via a facile method. The resultant composite consists of numerous Ag3PO4 nanoparticles with diameter less than 10nm, and these nanoparticles deposit onto the TiO2 nanoparticles surface forming a heterostructure. N2 adsorption-desorption measurements have suggested that the composite was porous with relative high surface area. Studies of the photocatalytic activity and stability of heterostructured Ag3PO4/m-TiO2 for the degradation of methylene blue (MB) have indicated that its visible light photocatalytic performance was improved compared with pure Ag3PO4 and Ag3PO4/m-TiO2, and exhibited excellent photocatalytic stability. The performance was improved attributing to three aspects: (1) the large specific surface area enhanced the adsorption of MB; (2) numerous pores enlarged the contact area between photocatalyst and MB; (3) the most importantly, depositing Ag3PO4 onto the surface of TiO2 facilitated the separation of electron and hole pairs, which also elevates the photocatalytic performance. Furthermore, the photocatalytic mechanism also has been discussed. Compare with Ag3PO4, the Ag weight percent of Ag3PO4/m-TiO2 decreases from 77% to 20.8%, significantly reducing the cost of photocatalyst. Copyright © 2015 Elsevier Inc. All rights reserved.

  16. Quantum emitters coupled to circular nanoantennas for high-brightness quantum light sources

    Science.gov (United States)

    Abudayyeh, Hamza A.; Rapaport, Ronen

    2017-09-01

    Engineering the directionality and emission rate of quantum light sources is essential in the development of modern quantum applications. In this work we use numerical calculations to optimise the brightness of a broadband quantum emitter positioned in a hybrid metal-dielectric circular periodic nanoantenna. The optimised structure features a photon collection efficiency of 74 % (82 % ) and a photon flux enhancement of over 10 (6) into a numerical aperture of 0.22 (0.50), respectively, corresponding to a direct coupling into two types of multi-mode fibres. To enhance the emission rate, we present a new circular nanoantenna design where a quantum emitter is attached to a silver nanocone at the centre of the antenna. After optimisation, we find a collection efficiency of 61 % (78 % ) into a numerical aperture of 0.22 (0.50), giving a brightness enhancement of 1000 (600) for an unpolarised emitter. The enhancements in both structures are broadband due to the low-quality factor of the device and are therefore ideal for room-temperature sources. This type of a scalable design can be utilised towards on-chip, high-brightness quantum light sources operating at room temperature.

  17. Secondary flows in the cooling channels of the high-performance light-water reactor

    Energy Technology Data Exchange (ETDEWEB)

    Laurien, E.; Wintterle, Th. [Stuttgart Univ., Institute for Nuclear Technolgy and Energy Systems (IKE) (Germany)

    2007-07-01

    The new design of a High-Performance Light-Water Reactor (HPLWR) involves a three-pass core with an evaporator region, where the compressed water is heated above the pseudo-critical temperature, and two superheater regions. Due to the strong dependency of the supercritical water density on the temperature significant mass transfer between neighboring cooling channels is expected if the temperature is unevenly distributed across the fuel element. An inter-channel flow is then superimposed to the secondary flow vortices induced by the non-isotropy of turbulence. In order to gain insight into the resulting flow patterns as well as into temperature and density distributions within the various subchannels of the fuel element CFD (Computational Fluid Dynamics) calculations for the 1/8 fuel element are performed. For simplicity adiabatic boundary conditions at the moderator box and the fuel element box are assumed. Our investigation confirms earlier results obtained by subchannel analysis that the axial mass flux is significantly reduced in the corner subchannel of this fuel element resulting in a net mass flux towards the neighboring subchannels. Our results provide a first estimation of the magnitude of the secondary flows in the pseudo-critical region of a supercritical light-water reactor. Furthermore, it is demonstrated that CFD is an efficient tool for investigations of flow patterns within nuclear reactor fuel elements. (authors)

  18. Surface Modification of Light Alloys by Low-Energy High-Current Pulsed Electron Beam

    Directory of Open Access Journals (Sweden)

    X. D. Zhang

    2012-01-01

    Full Text Available This paper reviews results obtained by the research groups developing the low-energy high-current pulsed electron beam (LEHCPEB in Dalian (China and Metz (France on the surface treatment of light alloys. The pulsed electron irradiation induces an ultra-fast thermal cycle at the surface combined with the formation of thermal stress and shock waves. As illustrated for Mg alloys and Ti, this results in deep subsurface hardening (over several 100 μm which improves the wear resistance. The analysis of the top surface melted surface of light alloys also often witnesses evaporation and condensation of chemical species. This phenomenon can significantly modify the melt chemistry and was also suggested to lead to the development of specific solidification textures in the rapidly solidified layer. The potential use of the LEHCPEB technique for producing thermomechanical treatments under the so-called heating mode and, thus, modify the surface crystallographic texture, and enhance solid-state diffusion is also demonstrated in the case of the FeAl intermetallic compound.

  19. The HVAC Challenges of Upgrading an Old Lab for High-end Light Microscopes

    Science.gov (United States)

    Richard, R.; Martone, P.; Callahan, L.M.

    2014-01-01

    The University of Rochester Medical Center forms the centerpiece of the University of Rochester's health research, teaching, patient care, and community outreach missions. Within this large facility of over 5 million square feet, demolition and remodeling of existing spaces is a constant activity. With more than $145 million in federal research funding, lab space is frequently repurposed and renovated to support this work. The URMC Medical Center Facilities Organization supporting small to medium space renovations is constantly challenged and constrained by the existing mechanical infrastructure and budgets to deliver a renovated space that functions within the equipment environmental parameters. One recent project, sponsored by the URMC Shared Resources Laboratory, demonstrates these points. The URMC Light Microscopy Shared Resource Laboratory requested renovation of a 121 sq. ft. room in a 40 year old building which would enable placement of a laser capture microdissection microscope and a Pascal 5 laser scanning confocal microscope with the instruments separated by a blackout curtain. This poster discusses the engineering approach implemented to bring an older lab into the environmental specifications needed for the proper operation of the high-end light microscopes.

  20. Towards high-capacity fibre-optic communications at the speed of light in vacuum

    Science.gov (United States)

    Poletti, F.; Wheeler, N. V.; Petrovich, M. N.; Baddela, N.; Numkam Fokoua, E.; Hayes, J. R.; Gray, D. R.; Li, Z.; Slavík, R.; Richardson, D. J.

    2013-04-01

    Wide-bandwidth signal transmission with low latency is emerging as a key requirement in a number of applications, including the development of future exaflop-scale supercomputers, financial algorithmic trading and cloud computing. Optical fibres provide unsurpassed transmission bandwidth, but light propagates 31% slower in a silica glass fibre than in vacuum, thus compromising latency. Air guidance in hollow-core fibres can reduce fibre latency very significantly. However, state-of-the-art technology cannot achieve the combined values of loss, bandwidth and mode-coupling characteristics required for high-capacity data transmission. Here, we report a fundamentally improved hollow-core photonic-bandgap fibre that provides a record combination of low loss (3.5 dB km-1) and wide bandwidth (160 nm), and use it to transmit 37 × 40 Gbit s-1 channels at a 1.54 µs km-1 faster speed than in a conventional fibre. This represents the first experimental demonstration of fibre-based wavelength division multiplexed data transmission at close to (99.7%) the speed of light in vacuum.

  1. Highly stable cesium lead iodide perovskite quantum dot light-emitting diodes

    Science.gov (United States)

    Zou, Chen; Huang, Chun-Ying; Sanehira, Erin M.; Luther, Joseph M.; Lin, Lih Y.

    2017-11-01

    Recently, all-inorganic perovskites such as CsPbBr3 and CsPbI3, have emerged as promising materials for light-emitting applications. While encouraging performance has been demonstrated, the stability issue of the red-emitting CsPbI3 is still a major concern due to its small tolerance factor. Here we report a highly stable CsPbI3 quantum dot (QD) light-emitting diode (LED) with red emission fabricated using an improved purification approach. The device achieved decent external quantum efficiency (EQE) of 0.21% at a bias of 6 V and outstanding operational stability, with a L 70 lifetime (EL intensity decreases to 70% of starting value) of 16 h and 1.5 h under a constant driving voltage of 5 V and 6 V (maximum EQE operation) respectively. Furthermore, the device can work under a higher voltage of 7 V (maximum luminance operation) and retain 50% of its initial EL intensity after 500 s. These findings demonstrate the promise of CsPbI3 QDs for stable red LEDs, and suggest the feasibility for electrically pumped perovskite lasers with further device optimizations.

  2. Hybrid metal grid-polymer-carbon nanotube electrodes for high luminance organic light emitting diodes

    Science.gov (United States)

    Sam, F. Laurent M.; Dabera, G. Dinesha M. R.; Lai, Khue T.; Mills, Christopher A.; Rozanski, Lynn J.; Silva, S. Ravi P.

    2014-08-01

    Organic light emitting diodes (OLEDs) incorporating grid transparent conducting electrodes (TCEs) with wide grid line spacing suffer from an inability to transfer charge carriers across the gaps in the grids to promote light emission in these areas. High luminance OLEDs fabricated using a hybrid TCE composed of poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS PH1000) or regioregular poly(3-hexylthiophene)-wrapped semiconducting single-walled carbon nanotubes (rrP3HT-SWCNT) in combination with a nanometre thin gold grid are reported here. OLEDs fabricated using the hybrid gold grid/PH1000 TCE have a luminance of 18 000 cd m-2 at 9 V; the same as the reference indium tin oxide (ITO) OLED. The gold grid/rrP3HT-SWCNT OLEDs have a lower luminance of 8260 cd m-2 at 9 V, which is likely due to a rougher rrP3HT-SWCNT surface. These results demonstrate that the hybrid gold grid/PH1000 TCE is a promising replacement for ITO in future plastic electronics applications including OLEDs and organic photovoltaics. For applications where surface roughness is not critical, e.g. electrochromic devices or discharge of static electricity, the gold grid/rrP3HT-SWCNT hybrid TCE can be employed.

  3. Blue Quantum Dot Light-Emitting Diodes with High Electroluminescent Efficiency.

    Science.gov (United States)

    Wang, Lishuang; Lin, Jie; Hu, Yongsheng; Guo, Xiaoyang; Lv, Ying; Tang, Zhaobing; Zhao, Jialong; Fan, Yi; Zhang, Nan; Wang, Yunjun; Liu, Xingyuan

    2017-11-08

    High-efficiency blue CdSe/ZnS quantum dots (QDs) have been synthesized for display application with emission peak over 460 nm with the purpose of reducing the harmful effect of short-wavelength light to human eyes. To reach a better charge balance, different size ZnO nanoparticles (NPs) were synthesized and electrical properties of ZnO NPs were analyzed. Quantum dot light-emitting diodes (QLEDs) based on as-prepared blue QDs and optimized ZnO NPs have been successfully fabricated. Using small-size ZnO NPs, we have obtained a maximum current efficiency (CE) of 14.1 cd A(-1) and a maximum external quantum efficiency (EQE) of 19.8% for QLEDs with an electroluminescence (EL) peak at 468 nm. To the best of our knowledge, this EQE is the highest value in comparison to the previous reports. The CIE 1931 color coordinates (0.136, 0.078) of this device are quite close to the standard (0.14, 0.08) of National Television System Committee (NTSC) 1953. The color saturation blue QLEDs show great promise for use in next-generation full-color displays.

  4. Highly efficient conductivity modulation of cinnamate-based light-responsive ionic liquids in aqueous solutions.

    Science.gov (United States)

    Yang, Jie; Wang, Huiyong; Wang, Jianji; Zhang, Yue; Guo, Zhongjia

    2014-12-11

    A new class of cinnamate-based light-responsive ionic liquids was synthesized and characterized, and these ionic liquids with longer alkyl chains showed a remarkable increase in ionic conductivity under UV light irradiation in aqueous solutions.

  5. Micro-V covering materials with high light transmittance for solar collectors

    Energy Technology Data Exchange (ETDEWEB)

    Sonneveld, P.J.; Swinkels, G.L.A.M. [Wageningen UR, A and F (Netherlands)

    2004-07-01

    Maximal light transmittance of the covering material is important for solar collectors maximising yield of the system. Furthermore a second sheet of covering material can be applied with low light loss to increase thermal insulation. Therefore research is aimed at improving light transmission. Ray tracing method has been applied to design the optimal geometry of the material. Light transmission, thermal insulation, structural performance and yield aspects of solar collectors are combined in this research with glass as basic covering material. (orig.)

  6. Low-frequency wide-field fluorescence lifetime imaging using a high-power near-infrared light-emitting diode light source

    OpenAIRE

    Gioux, Sylvain; Lomnes, Stephen J.; Choi, Hak Soo; Frangioni, John V.

    2010-01-01

    Fluorescence lifetime imaging (FLi) could potentially improve exogenous near-infrared (NIR) fluorescence imaging, because it offers the capability of discriminating a signal of interest from background, provides real-time monitoring of a chemical environment, and permits the use of several different fluorescent dyes having the same emission wavelength. We present a high-power, LED-based, NIR light source for the clinical translation of wide-field (larger than 5 cm in diameter) FLi at frequenc...

  7. Flash light sintered copper precursor/nanoparticle pattern with high electrical conductivity and low porosity for printed electronics

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Wan-Ho; Hwang, Hyun-Jun [Department of Mechanical Convergence Engineering, Hanyang University, 17 Haendang-Dong, Seongdong-Gu, Seoul 133-791 (Korea, Republic of); Kim, Hak-Sung, E-mail: kima@hanyang.ac.kr [Department of Mechanical Convergence Engineering, Hanyang University, 17 Haendang-Dong, Seongdong-Gu, Seoul 133-791 (Korea, Republic of); Institute of Nano Science and Technology, Hanyang University, Seoul 133-791 (Korea, Republic of)

    2015-04-01

    In this work, the hybrid copper inks with precursor and nanoparticles were fabricated and sintered via flash light irradiation to achieve highly conductive electrode pattern with low porosity. The hybrid copper ink was made of copper nanoparticles and various copper precursors (e.g., copper(II) chloride, copper(II) nitrate trihydrate, copper(II) sulfate pentahydrate and copper(II) trifluoroacetylacetonate). The printed hybrid copper inks were sintered at room temperature and under ambient conditions using an in-house flash light sintering system. The effects of copper precursor weight fraction and the flash light irradiation conditions (light energy and pulse duration) were investigated. Surfaces of the sintered hybrid copper patterns were analyzed using a scanning electron microscope. Also, spectroscopic characterization techniques such as Fourier transform infrared spectroscopy and X-ray diffraction were used to investigate the crystal phases of the flash light sintered copper precursors. High conductivity hybrid copper patterns (27.3 μΩ cm), which is comparable to the resistivity of bulk copper (1.68 μΩ cm) were obtained through flash light sintering at room temperature and under ambient conditions. - Highlights: • The hybrid copper inks with precursor and nanoparticles were fabricated. • The hybrid copper ink was sintered via flash light irradiation. • The resistivity of sintered hybrid copper ink was 27.3 μΩ cm. • Highly conductive copper film with low porosity could be achieved.

  8. An integrated analysis of molecular acclimation to high light in the marine diatom Phaeodactylum tricornutum

    DEFF Research Database (Denmark)

    Nymark, Marianne; Valle, Kristin C; Brembu, Tore

    2009-01-01

    Photosynthetic diatoms are exposed to rapid and unpredictable changes in irradiance and spectral quality, and must be able to acclimate their light harvesting systems to varying light conditions. Molecular mechanisms behind light acclimation in diatoms are largely unknown. We set out to investiga...

  9. Purifying Synthetic High-Strength Wastewater by Microalgae Chlorella Vulgaris Under Various Light Emitting Diode Wavelengths and Intensities

    Directory of Open Access Journals (Sweden)

    Zhigang Ge

    2013-06-01

    Full Text Available The high-strength wastewater is now well known as a threat to the natural water since it is highly possible to arouse water eutrophication or algal blooms. The effects of various light emitting diode wavelengths and intensities on the microalgae biological wastewater treatment system was studied in this research. The various nutrient removals and economic efficiencies represented similar variation trends, and these variations under both high C and N loading treatments were similar too. The order for microalgae C. vulgaris reproduction in terms of dry weight and nutrient removal efficiency both were red > white > yellow > blue, under high carbon and nitrogen loading treatments, indicating that the red light was the optimum light wavelength. Furthermore, considering the optimal light intensity in terms of nutrient removal efficiency was 2500 and 2000 μmol/m2•s, while in terms of economic efficiency was 1000, 1500 and 2000 μmol/m2•s. Therefore, the optimum light intensity was found to be 2000 μmol/m2•s. In addition, the optimal experimental illumination time was determined as 120 h. The Chlorella vulgaris microalgae biological wastewater treatment system utilized in this research was able to purify the high-strength carbon and nitrogen wastewater effectively under optimum light wavelength and intensity.

  10. Purifying synthetic high-strength wastewater by microalgae chlorella vulgaris under various light emitting diode wavelengths and intensities

    Science.gov (United States)

    2013-01-01

    The high-strength wastewater is now well known as a threat to the natural water since it is highly possible to arouse water eutrophication or algal blooms. The effects of various light emitting diode wavelengths and intensities on the microalgae biological wastewater treatment system was studied in this research. The various nutrient removals and economic efficiencies represented similar variation trends, and these variations under both high C and N loading treatments were similar too. The order for microalgae C. vulgaris reproduction in terms of dry weight and nutrient removal efficiency both were red > white > yellow > blue, under high carbon and nitrogen loading treatments, indicating that the red light was the optimum light wavelength. Furthermore, considering the optimal light intensity in terms of nutrient removal efficiency was 2500 and 2000 μmol/m2•s, while in terms of economic efficiency was 1000, 1500 and 2000 μmol/m2•s. Therefore, the optimum light intensity was found to be 2000 μmol/m2•s. In addition, the optimal experimental illumination time was determined as 120 h. The Chlorella vulgaris microalgae biological wastewater treatment system utilized in this research was able to purify the high-strength carbon and nitrogen wastewater effectively under optimum light wavelength and intensity. PMID:24499586

  11. Is Ambient Light during the High Arctic Polar Night Sufficient to Act as a Visual Cue for Zooplankton?

    Directory of Open Access Journals (Sweden)

    Jonathan H Cohen

    Full Text Available The light regime is an ecologically important factor in pelagic habitats, influencing a range of biological processes. However, the availability and importance of light to these processes in high Arctic zooplankton communities during periods of 'complete' darkness (polar night are poorly studied. Here we characterized the ambient light regime throughout the diel cycle during the high Arctic polar night, and ask whether visual systems of Arctic zooplankton can detect the low levels of irradiance available at this time. To this end, light measurements with a purpose-built irradiance sensor and coupled all-sky digital photographs were used to characterize diel skylight irradiance patterns over 24 hours at 79°N in January 2014 and 2015. Subsequent skylight spectral irradiance and in-water optical property measurements were used to model the underwater light field as a function of depth, which was then weighted by the electrophysiologically determined visual spectral sensitivity of a dominant high Arctic zooplankter, Thysanoessa inermis. Irradiance in air ranged between 1-1.5 x 10-5 μmol photons m-2 s-1 (400-700 nm in clear weather conditions at noon and with the moon below the horizon, hence values reflect only solar illumination. Radiative transfer modelling generated underwater light fields with peak transmission at blue-green wavelengths, with a 465 nm transmission maximum in shallow water shifting to 485 nm with depth. To the eye of a zooplankter, light from the surface to 75 m exhibits a maximum at 485 nm, with longer wavelengths (>600 nm being of little visual significance. Our data are the first quantitative characterisation, including absolute intensities, spectral composition and photoperiod of biologically relevant solar ambient light in the high Arctic during the polar night, and indicate that some species of Arctic zooplankton are able to detect and utilize ambient light down to 20-30m depth during the Arctic polar night.

  12. Structural Optimization of High-Power AlGaInP Resonant Cavity Light-Emitting Diodes for Visible Light Communications

    Science.gov (United States)

    Oh, Hwa Sub; Hue Joo, Jee; Lee, Jin Hong; Hyeob Baek, Jong; Seo, Jae Won; Kwak, Joon Seop

    2008-08-01

    For developing high-power resonant cavity light-emitting diodes (RCLEDs) appropriate for visible light communications, we have investigated the effect of reflectivity of a p-side distributed Bragg reflector (p-DBR) and the number of quantum wells (QWs) in active layers on the spectral characteristics and optical power of RCLEDs. As the reflectivity of p-DBR increased, the full width at half maximum (FWHM) of the electroluminescence (EL) spectrum was reduced from 12.3 to 3.6 nm, whereas the relative integrated intensity decreased from 1.0 to 0.37, which can be attributed to the improvement of spectral purity of peaks with in-phase condition. As the number of QWs decreased, optical power increased owing to the reduction of the optical loss of recycling light in the active region. Using the optimized structural conditions, we demonstrated RCLEDs having a modulation speed up to 130 MHz in free space, which shows that the optimized RCLED structure is a promising candidate for visible light communications (VLCs).

  13. Synthesis of highly functionalized polycyclic quinoxaline derivatives using visible-light photoredox catalysis.

    Science.gov (United States)

    He, Zhi; Bae, Minwoo; Wu, Jie; Jamison, Timothy F

    2014-12-22

    A mild and facile method for preparing highly functionalized pyrrolo[1,2-a]quinoxalines and other nitrogen-rich heterocycles, each containing a quinoxaline core or an analogue thereof, has been developed. The novel method features a visible-light-induced decarboxylative radical coupling of ortho-substituted arylisocyanides and radicals generated from phenyliodine(III) dicarboxylate reagents and exhibits excellent functional group compatibility. A wide range of quinoxaline heterocycles have been prepared. Finally, a telescoped preparation of these polycyclic compounds by integration of the in-line isocyanide formation and photochemical cyclization has been established in a three-step continuous-flow system. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Fiber-optic, anti-cycling, high pressure sodium street light control. Final technical progress report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-05-01

    This is the Final Technical Progress Report on a project to develop and market a Fiber-Optic Anti-Cycling High Pressure Sodium Street Light Control. The field test units are now being made with a single vertical PC board design and contains a computer-on-a-chip or PROM IC to take the place of the majority of the components previously contained on the upper logic board. This will reduce the final costs of the unit when it is in production and increase the control`s flexibility. The authors have finished the soft tooling and have made the 400 plastic cases for the field test units. The new configuration of the cases entails a simplified design of the control shell which will have the lenses cast in place. The shell and base plastics are now finished and in final assembly awaiting the completion of the PC boards.

  15. Highly predictable photosynthetic production in natural macroalgal communities from incoming and absorbed light

    DEFF Research Database (Denmark)

    Middelboe, Anne Lise; Sand-Jensen, Kaj; Binzer, Thomas

    2006-01-01

    height and species richness. The close relationship of community photosynthesis to irradiance is due to the fact that (1) large differences in thallus photosynthesis of individual species are averaged out in communities composed of several species, (2) seasonal replacement of species keeps communities......Photosynthesis-irradiance relationships of macroalgal communities and thalli of dominant species in shallow coastal Danish waters were measured over a full year to test how well community production can be predicted from environmental (incident irradiance and temperature) and community variables...... (canopy absorptance, species number and thallus metabolism). Detached thalli of dominant species performed optimally at different times of the year, but showed no general seasonal changes in photosynthetic features. Production capacity of communities at high light varied only 1.8-fold over the year...

  16. High energy QCD at NLO: from light-cone wave function to JIMWLK evolution

    Science.gov (United States)

    Lublinsky, Michael; Mulian, Yair

    2017-05-01

    Soft components of the light cone wave-function of a fast moving projectile hadron is computed in perturbation theory to the third order in QCD coupling constant. At this order, the Fock space of the soft modes consists of one-gluon, two-gluon, and a quark-antiquark states. The hard component of the wave-function acts as a non-Abelian background field for the soft modes and is represented by a valence charge distribution that accounts for non-linear density effects in the projectile. When scattered off a dense target, the diagonal element of the S-matrix reveals the Hamiltonian of high energy evolution, the JIMWLK Hamiltonian. This way we provide a new direct derivation of the JIMWLK Hamiltonian at the Next-to-Leading Order.

  17. Coupling Light from a High-Q Microsphere Resonator Using a UV-induced Surface Grating

    Science.gov (United States)

    Ilchenko, V. S.; Starodubov, D. S.; Gorodetsky, M. L.; Maleki, L.; Feinberg, J.

    2000-01-01

    High-Q microspheres with whispering-gallery modes have very narrow resonances that can be used for fiber-optic filters, ultra-compact narrow-linewidth lasers and optical/microwave oscillators. Whispering-gallery modes were previously excited in microspheres using evanescent optical fields. The necessary phase synchronism was obtained by adjusting the incident angle of input light beam (prism coupler) or adjustment of the waveguide propagation constant (fiber taper coupler). For many applications, however, bulky near-field couplers are undesirable. They compromise the symmetry and generate stray fields. Also, the control of coupling is crucial for the performance of microsphere resonators: in analogy with radio frequency circuits, the loading Q-factor should be less than the intrinsic Q-factor, Q(sub L) less than or equal to Q(sub O). Ideally one should combine a stable coupling element and a resonator into a single microsphere component.

  18. Detecting and locating light atoms from high-resolution STEM images: The quest for a single optimal design.

    Science.gov (United States)

    Gonnissen, J; De Backer, A; den Dekker, A J; Sijbers, J; Van Aert, S

    2016-11-01

    In the present paper, the optimal detector design is investigated for both detecting and locating light atoms from high resolution scanning transmission electron microscopy (HR STEM) images. The principles of detection theory are used to quantify the probability of error for the detection of light atoms from HR STEM images. To determine the optimal experiment design for locating light atoms, use is made of the so-called Cramér-Rao Lower Bound (CRLB). It is investigated if a single optimal design can be found for both the detection and location problem of light atoms. Furthermore, the incoming electron dose is optimised for both research goals and it is shown that picometre range precision is feasible for the estimation of the atom positions when using an appropriate incoming electron dose under the optimal detector settings to detect light atoms. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. First Light Achieved at the new Mt.Evans High Altitude Observatory

    Science.gov (United States)

    Stencel, R. E.

    1997-12-01

    During August 1997, first light images were obtained with the new Meyer Binocular Telescope, a twin 0.72 meter RC system, located at the Meyer- Womble Observatory atop 14,268 ft Mt.Evans, Colorado. The site is along a treeless high ridge which frequently enjoys laminar airflow and good seeing. The telescope and building also include thermal and airflow management systems for seeing optimization. Finally, a 5 element adaptive optics system that is being tested at Yerkes Observatory, should be able to correct the native seeing to nearly the limit of optical performance. For details on all of the above, please refer to my website: www.du.edu/ rstencel. The high altitude of Mt.Evans makes it ideal for mid-infrared studies, and we anticipate pursuing mid-IR imaging and spectroscopy from this site. Mark 2 of our TNTCAM (Klebe et al.-this meeting) is now in design stage, thanks to an NSF MRI grant. The spectrometer, TGIRS (Creech-Eakman et al. 1996 BAAS 28: 1372) has also achieved first light in the lab. We plan to use both at the new mountaintop facility. Another interesting feature of the new observatory is its photovoltaic energy supply for continuous power, sponsored in part by the Renewable Energy Trust, National Renewable Energy Lab and the Colorado Office of Energy Conservation. Denver University is interested in forming partnerships with other programs in order to make best use of this new resource for educational research in astronomy and astrophysics. This can include REU-style student summer visits, instrument testing and/or observational studies. I am pleased to acknowledge sponsorship by the Estate of William Herschel Womble, and the Meyer Foundation.

  20. The High Energy Light Isotope eXperiment (HELIX): Ohio State Tasks

    Science.gov (United States)

    Beatty, James

    We propose to join the High Energy Light Isotope eXperiment (HELIX), a balloon-borne magnetic spectrometer designed to measure the isotopic composition of cosmic ray nuclei from hydrogen to neon, with particular emphasis on the important Be-10/Be-9 `'clock' isotopic ratio.HELIX is a collaborative experiment headed by Scott Wakely (Chicago), with collaborators from Indiana University, Michigan, Penn State, and Northern Kentucky University. The HELIX instrument is designed to make measurements of the composition of light cosmic rays in the energy range from below 1 GeV/n to 5 GeV/n in its initial phase, with a specific emphasis on the determination of astrophysically important isotopic abundance ratios. Measurements of this kind at lower energies have in the past provided profound insights into the nature and origin of cosmic rays, revealing, for instance, information about acceleration and confinement timescales, and exposing some conspicuous discrepancies between solar and cosmic-ray abundances. We propose to contribute to HELIX by enhancing the mass resolution of the instrument and thus the range of masses and energies that can be studied, and by laying the technical foundation for extended operation of the magnet for a full 14-day Antarctic flight. The mass resolution will be enhanced by improving the rigidity resolution of the spectrometer by adding high-resolution silicon-strip tracking sensors repurposed from the Fermilab CDF inner tracker to augment the drift chamber, and by increasing the number of sensors in the RICH focal plane from 175 to 275. We will also develop an in-flight helium transfer process and demonstrate this capability in a CONUS test flight, and prepare a design for an auxiliary helium dewar and in-flight helium transfer system for use in future HELIX flights. This proposal is responsive to NASA's Strategic Objective 1.6: "Discover how the universe works, explore how it began and evolved, and search for life on planets around other stars."

  1. High-resolution deep imaging of live cellular spheroids with light-sheet-based fluorescence microscopy.

    Science.gov (United States)

    Pampaloni, Francesco; Ansari, Nariman; Stelzer, Ernst H K

    2013-04-01

    Conventional two-dimensional cell monolayers do not provide the geometrical, biochemical and mechanical cues found in real tissues. Cells in real tissues interact through chemical and mechanical stimuli with adjacent cells and via the extracellular matrix. Such a highly interconnected communication network extends along all three dimensions. This architecture is lost in two-dimensional cultures. Therefore, at least in many cases, two-dimensional cell monolayers do not represent a suitable in vitro tool to characterize accurately the biology of real tissues. Many studies performed over the last few years have demonstrated that the differences between three-dimensional and two-dimensional cultured cells are striking at the morphological and molecular levels and that three-dimensional cell cultures can be employed in order to shrink the gap between real tissues and in vitro cell models. End-point and long-term imaging of cellular and sub-cellular processes with fluorescence microscopy provides direct insight into the physiological behavior of three-dimensional cell cultures and their response to chemical or mechanical stimulation. Fluorescence imaging of three-dimensional cell cultures sets new challenges and imposes specific requirements concerning the choice of a suitable microscopy technique. Deep penetration into the specimen, high imaging speed and ultra-low intensity of the excitation light are key requirements. Light-sheet-based fluorescence microscopy (LSFM) offers a favorable combination of these requirements and is therefore currently established as the technique of choice for the study of three-dimensional cell cultures. This review illustrates the benefits of cellular spheroids in the life sciences and suggests that LSFM is essential for investigations of cellular and sub-cellular dynamic processes in three-dimensions over time and space.

  2. Testing a high-power LED based light source for hyperspectral imaging microscopy

    Science.gov (United States)

    Klomkaew, Phiwat; Mayes, Sam A.; Rich, Thomas C.; Leavesley, Silas J.

    2017-02-01

    Our lab has worked to develop high-speed hyperspectral imaging systems that scan the fluorescence excitation spectrum for biomedical imaging applications. Hyperspectral imaging can be used in remote sensing, medical imaging, reaction analysis, and other applications. Here, we describe the development of a hyperspectral imaging system that comprised an inverted Nikon Eclipse microscope, sCMOS camera, and a custom light source that utilized a series of high-power LEDs. LED selection was performed to achieve wavelengths of 350-590 nm. To reduce scattering, LEDs with low viewing angles were selected. LEDs were surface-mount soldered and powered by an RCD. We utilized 3D printed mounting brackets to assemble all circuit components. Spectraradiometric calibration was performed using a spectrometer (QE65000, Ocean Optics) and integrating sphere (FOIS-1, Ocean Optics). Optical output and LED driving current were measured over a range of illumination intensities. A normalization algorithm was used to calibrate and optimize the intensity of the light source. The highest illumination power was at 375 nm (3300 mW/cm2), while the lowest illumination power was at 515, 525, and 590 nm (5200 mW/cm2). Comparing the intensities supplied by each LED to the intensities measured at the microscope stage, we found there was a great loss in power output. Future work will focus on using two of the same LEDs to double the power and finding more LED and/or laser diodes and chips around the range. This custom hyperspectral imaging system could be used for the detection of cancer and the identification of biomolecules.

  3. Homogeneously embedded Pt nanoclusters on amorphous titania matrix as highly efficient visible light active photocatalyst material

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Vipul; Kumar, Suneel; Krishnan, Venkata, E-mail: vkn@iitmandi.ac.in

    2016-08-15

    A novel and facile technique, based on colloidal synthesis route, has been utilized for the preparation of homogeneously embedded Pt nanoclusters on amorphous titania matrix. The material has been thoroughly characterized using high resolution transmission electron microscopy, energy dispersive x-ray analysis, powder x-ray diffraction, optical and Raman spectroscopic techniques to understand the morphology, structure and other physical characteristics. The photocatalytic activity of the material under visible light irradiation was demonstrated by investigations on the degradation of two organic dyes (methylene blue and rhodamine B). In comparison to other Pt−TiO{sub 2} based nanomaterials (core-shell, doped nanostructures, modified nanotubes, decorated nanospheres and binary nanocomposites), the embedded Pt nanoclusters on titania was found to be highly efficient for visible light active photocatalytic applications. The enhanced catalytic performance could be attributed to the efficient charge separation and decreased recombination of the photo generated electrons and holes at the Pt-titania interface and the availability of multiple metal-metal oxide interfaces due to homogeneous embedment of Pt nanoclusters on amorphous titania. In essence, this work illustrates that homogeneous embedment of noble metal nanoparticles/nanoclusters on semiconductor metal oxide matrices can lead to tuning of the photophysical properties of the final material and eventually enhance its photocatalytic activity. - Highlights: • Homogeneously embedded Pt nanoclusters on amorphous titania matrix has been prepared. • Facile low temperature colloidal synthesis technique has been used. • Enhanced catalytic performance could be observed. • Work can pave way for tuning photocatalytic activity of composite materials.

  4. Antioxidant Metabolism during Acclimation of Begonia × erythrophylla to High Light Levels

    Science.gov (United States)

    BURRITT, DAVID J.; MACKENZIE, SUSAN

    2003-01-01

    This study examined the influence of high light levels on antioxidant metabolism and the photosynthetic properties of Begonia × erythrophylla leaves. The pigment composition of shaded leaves and those developing in full sunlight was typical of shade‐ and sun‐leaves, respectively. After 28 d in full sunlight, the preformed leaves of shade plants transferred to full sunlight (transferred‐leaves) showed photo‐bleaching with lower Chl (a + b) content and Chl a : Chl b ratios than shade‐leaves, with Chl (a + b) : carotenoid ratios not significantly different. The variable/maximal fluorescence (Fv/Fm) of sun‐leaves was not significantly different from that of shade‐leaves, but transferred‐leaves had reduced Fv : Fm ratios. Light response curves for the electron transport rate (ETR), the oxidation state of photosystem II (qP) and non‐photochemical quenching (NPQ) showed significant differences between the three leaf types, with transferred‐leaves not able to acclimate completely to full sunlight, having lower ETR, qP and NPQ values at high light levels than sun‐leaves. Transfer to full sunlight caused a rapid increase in H2O2 and lipid hyperoxides, and a slight increase in protein oxidation. Ascorbate and glutathione levels decreased rapidly, as did the size of the total glutathione pool and, in addition to the general oxidation of proteins, rapid decreases in both the initial and total activities of chloroplastic fructose‐1,6‐bisphosphatase and glyceraldehyde‐3‐phosphate dehydrogenase were observed. These results suggest that a more oxidizing cellular environment is the likely cause of the photo‐bleaching observed upon transfer of shade‐leaves to full sunlight. Acclimation of transferred‐leaves to full sunlight involved gradual increases in the activities of enzymes involved in antioxidant metabolism, including superoxide dismutase, catalase, glutathione reductase, ascorbate peroxidase, dehydroascorbate reductase and

  5. Live correlative light-electron microscopy to observe molecular dynamics in high resolution.

    Science.gov (United States)

    Kobayashi, Shouhei; Iwamoto, Masaaki; Haraguchi, Tokuko

    2016-08-01

    Fluorescence microscopy (FM) is a powerful tool for observing specific molecular components in living cells, but its spatial resolution is relatively low. In contrast, electron microscopy (EM) provides high-resolution information about cellular structures, but it cannot provide temporal information in living cells. To achieve molecular selectivity in imaging at high resolution, a method combining EM imaging with live-cell fluorescence imaging, known as live correlative light-EM (CLEM), has been developed. In this method, living cells are first observed by FM, fixed in situ during the live observation and then subjected to EM observation. Various fluorescence techniques and tools can be applied for FM, resulting in the generation of various modified methods that are useful for understanding cellular structure in high resolution. Here, we review the methods of CLEM and live-cell imaging associated with CLEM (live CLEM). Such methods can greatly advance the understanding of the function of cellular structures on a molecular level, and thus are useful for medical fields as well as for basic biology. © The Author 2016. Published by Oxford University Press on behalf of The Japanese Society of Microscopy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  6. Microwave synthesis of homogeneous and highly luminescent BCNO nanoparticles for the light emitting polymer materials

    Energy Technology Data Exchange (ETDEWEB)

    Iwasaki, Hideharu [Battery Materials Laboratory, Kurashiki Research Center, Kuraray Co., Ltd., 2045-1, Sakazu, Kurashiki, Okayama 710-0801 (Japan); Department of Chemical Engineering, Graduate School of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi Hiroshima 739 8527 (Japan); Ogi, Takashi, E-mail: ogit@hiroshima-u.ac.jp [Department of Chemical Engineering, Graduate School of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi Hiroshima 739 8527 (Japan); Iskandar, Ferry [Department of Physics, Institute of Technology Bandung, Ganesha 10, Bandung 40132, West Java (Indonesia); Aishima, Kana; Okuyama, Kikuo [Department of Chemical Engineering, Graduate School of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi Hiroshima 739 8527 (Japan)

    2015-10-15

    Nano-sized boron carbon oxynitride (BCNO) phosphors around 50 nm containing no rare earth metal and free from color heterogeneity were synthesized from mixtures of boric acid, urea, and citric acid by microwave heating with substantially shorter reaction times and lower temperatures than in the conventional BCNO preparation method such as electric-furnace heating. The emission wavelength of the phosphors varied with the mixing ratio of raw materials and it was found that lowering the proportion of urea to boric acid or citric acid tended to increase the internal quantum yield and shorten the emission wavelength under excitation at 365 nm. It was also found for the first time that a light-emitting polymer could be synthesized from a mixture of the prepared BCNO nanoparticles and a polyvinyl alcohol. This polymer composite exhibited uniform dispersion and stabilization of the luminescence and had a high internal quantum yield of 54%, which was higher than that of the phosphor alone. - Highlights: • Nano-sized BCNO phosphor was synthesized via microwave heating. • BCNO nanophosphor has homogeneous and high luminescence. • Emission wavelength was tunable by changing the ratio of precursor components. • BCNO nanophosphor can be easily dispersed in a polyvinyl alcohol. • BCNO–polymer composite exhibited uniform high internal quantum yield.

  7. Acne phototherapy using UV-free high-intensity narrow-band blue light: a three-center clinical study

    Science.gov (United States)

    Shalita, Alan R.; Harth, Yoram; Elman, Monica; Slatkine, Michael; Talpalariu, Gerry; Rosenberg, Yitzhak; Korman, Avner; Klein, Arieh

    2001-05-01

    Propionibacterium. acnes is a Gram positive, microaerophilic bacterium which takes a part in the pathogenesis of inflammatory acne. P. acnes is capable to produce high amounts endogenic porphyrins with no need of any trigger molecules. Light in the violet-blue range (407-420 nm) has been shown to exhibit a phototoxic effect on Propionibacterium acnes when irradiated in vitro. The purpose of our study was to test the clinical effects of a high intensity narrowband blue light source on papulo pustular acne. A total of 35 patients in 3 centers were treated twice a week with a high intensity metal halide lamp illuminating the entire face (20x20 cm2) or the back with visible light in the 407-420 nm range at an intensity of 90 mW/cm2 (CureLight Ltd.) for a total of 4 weeks. UV is totally cut off. In each treatment the patient was exposed to light for 8-15 minutes. After 8 treatments, 80% of the patients with mild to moderate papulo-pustular acne showed significant improvement at reducing the numbers of non- inflammatory, inflammatory and total facial lesions. Inflammatory lesion count decrease by a mean of 68%. No side effects to the treatment were noticed. In conclusion, full face or back illumination with the high intensity pure blue light we used exhibits a rapid significant decrease in acne lesions counts in 8 biweekly treatments.

  8. High light stress and the one-helix LHC-like proteins of the cryptophyte Guillardia theta.

    Science.gov (United States)

    Funk, Christiane; Alami, Meriem; Tibiletti, Tania; Green, Beverley R

    2011-07-01

    Cryptophytes like the cryptomonad Guillardia theta are part of the marine phytoplankton and therefore major players in global carbon and biogeochemical cycles. Despite the importance for the cell in being able to cope with large changes in illumination on a daily basis, very little is known about photoprotection mechanisms in cryptophytes. Here, we show that Guillardia theta is able to perform non-photochemical quenching, although none of the usual xanthophyll cycle pigments (e.g., zeaxanthin, diadinoxanthin, diatoxanthin) are present at detectable levels. Instead, acclimation to high light intensity seems to involve an increase of alloxanthin. Guillardia theta has genes for 2 one-helix "light-harvesting-like" proteins, related to some cyanobacterial genes which are induced in response to high light stress. Both the plastid-encoded gene (hlipP) and the nucleomorph-encoded gene (HlipNm) are expressed, but transcript levels decrease rather than increase during high light exposure, suggesting that they are not involved in a high light stress response. The HlipNm protein was detected with a specific antibody; expression was constant, independent of the light exposure. Copyright © 2011 Elsevier B.V. All rights reserved.

  9. Photosynthetic Properties and Potentials for Improvement of Photosynthesis in Pale Green Leaf Rice under High Light Conditions.

    Science.gov (United States)

    Gu, Junfei; Zhou, Zhenxiang; Li, Zhikang; Chen, Ying; Wang, Zhiqin; Zhang, Hao; Yang, Jianchang

    2017-01-01

    Light is the driving force of plant growth, providing the energy required for photosynthesis. However, photosynthesis is also vulnerable to light-induced damage caused by the production of reactive oxygen species (ROS). Plants have therefore evolved various protective mechanisms such as non-photochemical quenching (NPQ) to dissipate excessively absorbed solar energy as heat; however, photoinhibition and NPQ represent a significant loss in solar energy and photosynthetic efficiency, which lowers the yield potential in crops. To estimate light capture and light energy conversion in rice, a genotype with pale green leaves (pgl) and a normally pigmented control (Z802) were subjected to high (HL) and low light (LL). Chlorophyll content, light absorption, chloroplast micrographs, abundance of light-harvesting complex (LHC) binding proteins, electron transport rates (ETR), photochemical and non-photochemical quenching, and generation of ROS were subsequently examined. Pgl had a smaller size of light-harvesting chlorophyll antenna and absorbed less photons than Z802. NPQ and the generation of ROS were also low, while photosystem II efficiency and ETR were high, resulting in improved photosynthesis and less photoinhibition in pgl than Z802. Chlorophyll synthesis and solar conversion efficiency were higher in pgl under HL compared to LL treatment, while Z802 showed an opposite trend due to the high level of photoinhibition under HL. In Z802, excessive absorption of solar energy not only increased the generation of ROS and NPQ, but also exacerbated the effects of increases in temperature, causing midday depression in photosynthesis. These results suggest that photosynthesis and yield potential in rice could be enhanced by truncated light-harvesting chlorophyll antenna size.

  10. Photosynthetic Properties and Potentials for Improvement of Photosynthesis in Pale Green Leaf Rice under High Light Conditions

    Directory of Open Access Journals (Sweden)

    Junfei Gu

    2017-06-01

    Full Text Available Light is the driving force of plant growth, providing the energy required for photosynthesis. However, photosynthesis is also vulnerable to light-induced damage caused by the production of reactive oxygen species (ROS. Plants have therefore evolved various protective mechanisms such as non-photochemical quenching (NPQ to dissipate excessively absorbed solar energy as heat; however, photoinhibition and NPQ represent a significant loss in solar energy and photosynthetic efficiency, which lowers the yield potential in crops. To estimate light capture and light energy conversion in rice, a genotype with pale green leaves (pgl and a normally pigmented control (Z802 were subjected to high (HL and low light (LL. Chlorophyll content, light absorption, chloroplast micrographs, abundance of light-harvesting complex (LHC binding proteins, electron transport rates (ETR, photochemical and non-photochemical quenching, and generation of ROS were subsequently examined. Pgl had a smaller size of light-harvesting chlorophyll antenna and absorbed less photons than Z802. NPQ and the generation of ROS were also low, while photosystem II efficiency and ETR were high, resulting in improved photosynthesis and less photoinhibition in pgl than Z802. Chlorophyll synthesis and solar conversion efficiency were higher in pgl under HL compared to LL treatment, while Z802 showed an opposite trend due to the high level of photoinhibition under HL. In Z802, excessive absorption of solar energy not only increased the generation of ROS and NPQ, but also exacerbated the effects of increases in temperature, causing midday depression in photosynthesis. These results suggest that photosynthesis and yield potential in rice could be enhanced by truncated light-harvesting chlorophyll antenna size.

  11. Cavity Light-Emitting Diode for Durable, High-Brightness and High-Efficiency Lighting Applications: First Budget Period Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Yijian Shi

    2009-09-30

    A COLED device consists of a top electrode (anode) and a bottom electrode (cathode) separated by a thin dielectric layer. In this metal/dielectric stack, numerous small wells, or cavities, are etched through the top electrode and the dielectric layer. These cavities are subsequently filled with LEP molecules. When a voltage is applied between the top and bottom electrodes, holes (from the top electrode) and electrons (from the bottom electrode) are injected into the polymer. Light emission is generated upon recombination of holes and electrons within the polymer along the perimeters of cavities. Figure 1 compares the structures of the COLED and the traditional OLED. The existing COLED fabrication process flow is illustrated in Figure 2. A COLED can potentially be 5 times more efficient and can operate at as much as 100 times higher current density with much longer lifetime than an OLED. To fully realize these potential advantages, the COLED technology must overcome the following technical barriers, which were the technical focused points for Years 1 and 2 (Phase I) of this project: (1) Construct optimum thickness dielectric layer: In the traditional OLED structure, the optimal thickness of the LEP film is approximately 80-100 nm. In a COLED device, the effective LEP thickness roughly equals the thickness of the dielectric layer. Therefore, the optimal dielectric thickness for a COLED should also be roughly equal to 80-100 nm. Generally speaking, it is technically challenging to produce a defect-free dielectric layer at this thickness with high uniformity, especially over a large area. (2) Develop low-work-function cathode: A desired cathode should have a low work function that matches the lowest unoccupied molecular orbital (LUMO) level of the LEP molecules. This is usually achieved by using a low-work-function metal such as calcium, barium, lithium, or magnesium as the cathode. However, these metals are very vulnerable to oxygen and water. Since the cathode of the

  12. Spectroscopy of Highly Charged Tin Ions for AN Extreme Ultraviolet Light Source for Lithography

    Science.gov (United States)

    Torretti, Francesco; Windberger, Alexander; Ubachs, Wim; Hoekstra, Ronnie; Versolato, Oscar; Ryabtsev, Alexander; Borschevsky, Anastasia; Berengut, Julian; Crespo Lopez-Urrutia, Jose

    2017-06-01

    Laser-produced tin plasmas are the prime candidates for the generation of extreme ultraviolet (EUV) light around 13.5 nm in nanolithographic applications. This light is generated primarily by atomic transitions in highly charged tin ions: Sn^{8+}-Sn^{14+}. Due to the electronic configurations of these charge states, thousands of atomic lines emit around 13.5 nm, clustered in a so-called unresolved transition array. As a result, accurate line identification becomes difficult in this regime. Nevertheless, this issue can be circumvented if one turns to the optical: with far fewer atomic states, only tens of transitions take place and the spectra can be resolved with far more ease. We have investigated optical emission lines in an electron-beam-ion-trap (EBIT), where we managed to charge-state resolve the spectra. Based on this technique and on a number of different ab initio techniques for calculating the level structure, the optical spectra could be assigned [1,2]. As a conclusion the assignments of EUV transitions in the literature require corrections. The EUV and optical spectra are measured simultaneously in the controlled conditions of the EBIT as well as in a droplet-based laser-produced plasma source providing information on the contribution of Sn^{q+} charge states to the EUV emission. [1] A. Windberger, F. Torretti, A. Borschevsky, A. Ryabtsev, S. Dobrodey, H. Bekker, E. Eliav, U. Kaldor, W. Ubachs, R. Hoekstra, J.R. Crespo Lopez-Urrutia, O.O. Versolato, Analysis of the fine structure of Sn^{11+} - Sn^{14+} ions by optical spectroscopy in an electron beam ion trap, Phys. Rev. A 94, 012506 (2016). [2] F. Torretti, A. Windberger, A. Ryabtsev, S. Dobrodey, H. Bekker, W. Ubachs, R. Hoekstra, E.V. Kahl, J.C. Berengut, J.R. Crespo Lopez-Urrutia, O.O. Versolato, Optical spectroscopy of complex open 4d-shell ions Sn^{7+} - Sn^{10+}, arXiv:1612.00747

  13. High-space resolution imaging plate analysis of extreme ultraviolet (EUV) light from tin laser-produced plasmas.

    Science.gov (United States)

    Musgrave, Christopher S A; Murakami, Takehiro; Ugomori, Teruyuki; Yoshida, Kensuke; Fujioka, Shinsuke; Nishimura, Hiroaki; Atarashi, Hironori; Iyoda, Tomokazu; Nagai, Keiji

    2017-03-01

    With the advent of high volume manufacturing capabilities by extreme ultraviolet lithography, constant improvements in light source design and cost-efficiency are required. Currently, light intensity and conversion efficiency (CE) measurments are obtained by charged couple devices, faraday cups etc, but also phoshpor imaging plates (IPs) (BaFBr:Eu). IPs are sensitive to light and high-energy species, which is ideal for studying extreme ultraviolet (EUV) light from laser produced plasmas (LPPs). In this work, we used IPs to observe a large angular distribution (10°-90°). We ablated a tin target by high-energy lasers (1064 nm Nd:YAG, 1010 and 1011 W/cm2) to generate the EUV light. The europium ions in the IP were trapped in a higher energy state from exposure to EUV light and high-energy species. The light intensity was angular dependent; therefore excitation of the IP depends on the angle, and so highly informative about the LPP. We obtained high-space resolution (345 μm, 0.2°) angular distribution and grazing spectrometer (5-20 nm grate) data simultaneously at different target to IP distances (103 mm and 200 mm). Two laser systems and IP types (BAS-TR and BAS-SR) were also compared. The cosine fitting values from the IP data were used to calculate the CE to be 1.6% (SD ± 0.2) at 13.5 nm 2% bandwidth. Finally, a practical assessment of IPs and a damage issue are disclosed.

  14. Long-term adaptive response to high-frequency light signals in the unicellular photosynthetic eukaryote Dunaliella salina.

    Science.gov (United States)

    Combe, Charlotte; Hartmann, Philipp; Rabouille, Sophie; Talec, Amelie; Bernard, Olivier; Sciandra, Antoine

    2015-06-01

    Productivity of microalgal cultivation processes is tightly related to photosynthetic efficiency, and therefore to light availability at the cell scale. In an agitated, highly turbid suspension,the light signal received by a single phytoplankton cell moving in a dense culture is a succession of flashes. The growth characteristics of microalgae under such dynamic light conditions are thus fundamental information to understand nonlinear properties of the photosynthetic process and to improve cultivation process design and operation. Studies of the long term consequences of dynamic illumination regime on photosynthesis require a very specific experimental set-up where fast varying signals are applied on the long term. In order to investigate the growth response of the unicellular photosynthetic eukaryote Dunaliella salina (Chlorophyceae) to intermittent light exposure, different light regimes using LEDs with the same average total light dose were applied in continuous cultures. Flashing light with different durations of light flashes (△t of 30 s, 15 s, 2 s and 0.1 s) followed by dark periods of variable length (0.67 ≤ L:D ≤ 2) yielding flash frequencies in the range 0.017-5 Hz, were compared to continuous illumination. Specific growth rate, photosynthetic pigments, lipid productivity and elemental composition were measured on two duplicates for each irradiance condition. The different treatments of intermittent light led to specific growth rates ranging from 0.25 to 0.93 day(-1) . While photosynthetic efficiency was enhanced with increased flash frequency, no significant differences were observed in the particular carbon and chlorophyll content. Pigment analysis showed that within this range of flash frequency, cells progressively photoacclimated to the average light intensity. © 2015 Wiley Periodicals, Inc.

  15. High-power LED light sources for optical measurement systems operated in continuous and overdriven pulsed modes

    Science.gov (United States)

    Stasicki, Bolesław; Schröder, Andreas; Boden, Fritz; Ludwikowski, Krzysztof

    2017-06-01

    The rapid progress of light emitting diode (LED) technology has recently resulted in the availability of high power devices with unprecedented light emission intensities comparable to those of visible laser light sources. On this basis two versatile devices have been developed, constructed and tested. The first one is a high-power, single-LED illuminator equipped with exchangeable projection lenses providing a homogenous light spot of defined diameter. The second device is a multi-LED illuminator array consisting of a number of high-power LEDs, each integrated with a separate collimating lens. These devices can emit R, G, CG, B, UV or white light and can be operated in pulsed or continuous wave (CW) mode. Using an external trigger signal they can be easily synchronized with cameras or other devices. The mode of operation and all parameters can be controlled by software. Various experiments have shown that these devices have become a versatile and competitive alternative to laser and xenon lamp based light sources. The principle, design, achieved performances and application examples are given in this paper.

  16. Photosynthesis-dependent H2O2 transfer from chloroplasts to nuclei provides a high-light signalling mechanism.

    Science.gov (United States)

    Exposito-Rodriguez, Marino; Laissue, Pierre Philippe; Yvon-Durocher, Gabriel; Smirnoff, Nicholas; Mullineaux, Philip M

    2017-06-29

    Chloroplasts communicate information by signalling to nuclei during acclimation to fluctuating light. Several potential operating signals originating from chloroplasts have been proposed, but none have been shown to move to nuclei to modulate gene expression. One proposed signal is hydrogen peroxide (H2O2) produced by chloroplasts in a light-dependent manner. Using HyPer2, a genetically encoded fluorescent H2O2 sensor, we show that in photosynthetic Nicotiana benthamiana epidermal cells, exposure to high light increases H2O2 production in chloroplast stroma, cytosol and nuclei. Critically, over-expression of stromal ascorbate peroxidase (H2O2 scavenger) or treatment with DCMU (photosynthesis inhibitor) attenuates nuclear H2O2 accumulation and high light-responsive gene expression. Cytosolic ascorbate peroxidase over-expression has little effect on nuclear H2O2 accumulation and high light-responsive gene expression. This is because the H2O2 derives from a sub-population of chloroplasts closely associated with nuclei. Therefore, direct H2O2 transfer from chloroplasts to nuclei, avoiding the cytosol, enables photosynthetic control over gene expression.Multiple plastid-derived signals have been proposed but not shown to move to the nucleus to promote plant acclimation to fluctuating light. Here the authors use a fluorescent hydrogen peroxide sensor to provide evidence that H2O2 is transferred directly from chloroplasts to nuclei to control nuclear gene expression.

  17. Nanopatterned yttrium aluminum garnet phosphor incorporated film for high-brightness GaN-based white light emitting diodes

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Joong-yeon; Park, Sang-Jun [Department of Materials Science and Engineering, Korea University, Seoul 136-713 (Korea, Republic of); Ahn, Jinho, E-mail: jhahn@hanyang.ac.kr [Department of Material Science and Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Lee, Heon, E-mail: heonlee@korea.ac.kr [Department of Materials Science and Engineering, Korea University, Seoul 136-713 (Korea, Republic of)

    2014-11-03

    In this study, we fabricated high-brightness white light emitting diodes (LEDs) by developing a nanopatterned yttrium aluminum garnet (YAG) phosphor-incorporated film. White light can be obtained by mixing blue light from a GaN-based LED and yellow light of the YAG phosphor-incorporated film. If white light sources can be fabricated by exciting proper yellow phosphor using blue light, then these sources can be used instead of the conventional fluorescent lamps with a UV source, for backlighting of displays. In this work, a moth-eye structure was formed on the YAG phosphor-incorporated film by direct spin-on glass (SOG) printing. The moth-eye structures have been investigated to improve light transmittance in various optoelectronic devices, including photovoltaic solar cells, light emitting diodes, and displays, because of their anti-reflection property. Direct SOG printing, which is a simple, easy, and relatively inexpensive process, can be used to fabricate nanoscale structures. After direct SOG printing, the moth-eye structure with a diameter of 220 nm was formed uniformly on the YAG phosphor-incorporated film. As a result of moth-eye patterning on the YAG phosphor-incorporated film, the light output power of a white LED with a patterned YAG phosphor-incorporated film increased to up to 13% higher than that of a white LED with a non-patterned film. - Highlights: • GaN-based high-brightness white LED was prepared using patterned YAG phosphor-incorporated films. • Direct hydrogen silsesquioxane printing was used to form moth-eye patterns on the YAG films. • The electroluminescence intensity of the white LED was enhanced by up to 14.9%.

  18. Novel concepts for high-efficiency white organic light-emitting diodes

    Energy Technology Data Exchange (ETDEWEB)

    Schwartz, Gregor

    2007-07-01

    This work deals with novel concepts to realize high efficiency white OLEDs by combining fluorescent blue and phosphorescent green and orange emitters. A key point determining the maximum efficiency possible, as well as the device structure to be chosen to reach high efficiency, is the triplet exciton energy of the fluorescent blue emitter. If its triplet state is lower than that of the phosphorescent emitters, mutual exciton quenching can occur. This problem is solved by the first concept with spatial separation of the fluorescent blue from the phosphorescent emitters by a large-gap exciton blocking layer. To still realize exciton generation on both sides, the interlayer has to be ambipolar. On the other hand, if the triplet exciton energy of the fluorescent blue is higher than that of at least one of the phosphorescent emitters, appropriate arrangement of the emission layers makes a separation layer obsolete, since phosphorescence quenching does not occur anymore. Moreover, the intrinsically non-radiative triplet excitons of the fluorescent blue emitter may be harvested by the phosphor for light emission, which means that even 100% internal quantum efficiency is possible. The last chapter 6 deals with this second concept, where the main issue is to simultaneously achieve exciton harvesting as complete as possible and a balanced white emission spectrum by appropriately distributing singlet and triplet excitons to the used emitters. All emitters used in this work are commercially available and their molecular structure is disclosed in order to make the results transparent. (orig.)

  19. Fermi-LAT high-z active galactic nuclei and the extragalactic background light

    Science.gov (United States)

    Armstrong, Thomas; Brown, Anthony M.; Chadwick, Paula M.

    2017-10-01

    Observations of distant gamma-ray sources are hindered by the presence of the extragalactic background light (EBL). In order to understand the physical processes that result in the observed spectrum of sources, it is imperative that a good understanding of the EBL is included. In this work, an investigation into the imprint of the EBL on the observed spectra of high-redshift Fermi-LAT active galactic nuclei is presented. By fitting the spectrum below ˜10 GeV, an estimation of the unabsorbed intrinsic source spectrum is obtained; by applying this spectrum to data up to 300 GeV, it is then possible to derive a scaling factor for different EBL models. A second approach uses five sources (PKS 0426-380, 4C +55.17, Ton 116, PG 1246+586 and RBS 1432) that were found to exhibit very high energy (VHE) emission (Eγ > 100 GeV). Through Monte Carlo simulations, it is shown that the observation of VHE photons, despite the large distances of these objects, is consistent with current EBL models. Many of these sources would be observable with the upcoming ground-based observatory, the Cherenkov Telescope Array, leading to a better understanding of the EBL.

  20. A High Resolution, Light-Weight, Synthetic Aperture Radar for UAV Application

    Energy Technology Data Exchange (ETDEWEB)

    Doerry, A.W.; Hensley, W.H.; Stence, J.; Tsunoda, S.I. Pace, F.; Walker, B,C.; Woodring, M.

    1999-05-27

    (U) Sandia National Laboratories in collaboration with General Atomics (GA) has designed and built a high resolution, light-weight, Ku-band Synthetic Aperture Radar (SAR) known as "Lynx". Although Lynx can be operated on a wide variety of manned and unmanned platforms, its design is optimized for use on medium altitude Unmanned Aerial Vehicles (UAVS). In particular, it can be operated on the Predator, I-GNAT, and Prowler II platforms manufactured by GA. (U) The radar production weight is less than 120 lb and operates within a 3 GHz band from 15.2 GHz to 18.2 GHz with a peak output power of 320 W. Operating range is resolution and mode dependent but can exceed 45 km in adverse weather (4 mm/hr rain). Lynx has operator selectable resolution and is capable of 0.1 m resolution in spotlight mode and 0.3 m resolution in stripmap mode, over substantial depression angles (5 to 60 deg) and squint angles (broadside ±45 deg). Real-time Motion Compensation is implemented to allow high-quality image formation even during vehicle turns and other maneuvers.

  1. Frequency limits of high-efficiency non-resonant cavity light-emitting diodes

    Science.gov (United States)

    Heremans, Paul L.; Windisch, Reiner; Knobloch, Alexander; Potemans, J.; Dutta, Barundeb; Doehler, Gottfried H.; Borghs, Gustaaf

    1999-04-01

    In this paper, we present measurements of the switch-on times and of the switch-off times of non-resonant cavity light-emitting diodes, compared to those of conventional reference diodes. From this comparison, we infer that the high quantum efficiency of NRC-LED's is not achieved by photon recycling, but purely by efficient extraction of generated photons. This is further corroborated by the good matching that is achieved between the measured switch-on times and theoretical predictions of the switch-on times. The latter are calculated with a model that includes only the electrical charging of the active layer and assumes that photon recycling does not occur. It is furthermore shown that the switch-on can be made faster by switching the diode between a non-zero low-state and the required high state. Doing so, an open eye diagram is achieved at 622 Mbit/s for a NRC-LED having an external quantum efficiency of 17%.

  2. SUPER-CHANDRASEKHAR-MASS LIGHT CURVE MODELS FOR THE HIGHLY LUMINOUS TYPE Ia SUPERNOVA 2009dc

    Energy Technology Data Exchange (ETDEWEB)

    Kamiya, Yasuomi [Department of Astronomy, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Tanaka, Masaomi [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Nomoto, Ken' ichi [Kavli Institute for the Physics and Mathematics of the Universe, Todai Institutes for Advanced Study, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583 (Japan); Blinnikov, Sergei I. [Institute for Theoretical and Experimental Physics, 117218 Moscow (Russian Federation); Sorokina, Elena I. [Sternberg Astronomical Institute, Lomonosov Moscow State University, 119992 Moscow (Russian Federation); Suzuki, Tomoharu, E-mail: yasuomi.kamiya@ipmu.jp [College of Engineering, Chubu University, 1200 Matsumoto-cho, Kasugai, Aichi 487-8501 (Japan)

    2012-09-10

    Several highly luminous Type Ia supernovae (SNe Ia) have been discovered. Their high luminosities are difficult to explain with the thermonuclear explosions of Chandrasekhar-mass white dwarfs (WDs). In the present study, we estimate the progenitor mass of SN 2009dc, one of the extremely luminous SNe Ia, using the hydrodynamical models as follows. Explosion models of super-Chandrasekhar-mass (super-Ch-mass) WDs are constructed, and multi-color light curves (LCs) are calculated. The comparison between our calculations and the observations of SN 2009dc suggests that the exploding WD has a super-Ch mass of 2.2-2.4 M{sub Sun }, producing 1.2-1.4 M{sub Sun} of {sup 56}Ni, if the extinction by its host galaxy is negligible. If the extinction is significant, the exploding WD is as massive as {approx}2.8 M{sub Sun }, and {approx}1.8 M{sub Sun} of {sup 56}Ni is necessary to account for the observations. Whether the host-galaxy extinction is significant or not, the progenitor WD must have a thick carbon-oxygen layer in the outermost zone (20%-30% of the WD mass), which explains the observed low expansion velocity of the ejecta and the presence of carbon. Our estimate of the mass of the progenitor WD, especially for the extinction-corrected case, is challenging to the current scenarios of SNe Ia. Implications for the progenitor scenarios are also discussed.

  3. Extremely Vivid, Highly Transparent, and Ultrathin Quantum Dot Light-Emitting Diodes.

    Science.gov (United States)

    Choi, Moon Kee; Yang, Jiwoong; Kim, Dong Chan; Dai, Zhaohe; Kim, Junhee; Seung, Hyojin; Kale, Vinayak S; Sung, Sae Jin; Park, Chong Rae; Lu, Nanshu; Hyeon, Taeghwan; Kim, Dae-Hyeong

    2018-01-01

    Displaying information on transparent screens offers new opportunities in next-generation electronics, such as augmented reality devices, smart surgical glasses, and smart windows. Outstanding luminance and transparency are essential for such "see-through" displays to show vivid images over clear background view. Here transparent quantum dot light-emitting diodes (Tr-QLEDs) are reported with high brightness (bottom: ≈43 000 cd m-2 , top: ≈30 000 cd m-2 , total: ≈73 000 cd m-2 at 9 V), excellent transmittance (90% at 550 nm, 84% over visible range), and an ultrathin form factor (≈2.7 µm thickness). These superb characteristics are accomplished by novel electron transport layers (ETLs) and engineered quantum dots (QDs). The ETLs, ZnO nanoparticle assemblies with ultrathin alumina overlayers, dramatically enhance durability of active layers, and balance electron/hole injection into QDs, which prevents nonradiative recombination processes. In addition, the QD structure is further optimized to fully exploit the device architecture. The ultrathin nature of Tr-QLEDs allows their conformal integration on various shaped objects. Finally, the high resolution patterning of red, green, and blue Tr-QLEDs (513 pixels in.-1 ) shows the potential of the full-color transparent display. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Development of Gated Pinned Avalanche Photodiode Pixels for High-Speed Low-Light Imaging.

    Science.gov (United States)

    Resetar, Tomislav; De Munck, Koen; Haspeslagh, Luc; Rosmeulen, Maarten; Süss, Andreas; Puers, Robert; Van Hoof, Chris

    2016-08-15

    This work explores the benefits of linear-mode avalanche photodiodes (APDs) in high-speed CMOS imaging as compared to different approaches present in literature. Analysis of APDs biased below their breakdown voltage employed in single-photon counting mode is also discussed, showing a potentially interesting alternative to existing Geiger-mode APDs. An overview of the recently presented gated pinned avalanche photodiode pixel concept is provided, as well as the first experimental results on a 8 × 16 pixel test array. Full feasibility of the proposed pixel concept is not demonstrated; however, informative data is obtained from the sensor operating under -32 V substrate bias and clearly exhibiting wavelength-dependent gain in frontside illumination. The readout of the chip designed in standard 130 nm CMOS technology shows no dependence on the high-voltage bias. Readout noise level of 15 e - rms, full well capacity of 8000 e - , and the conversion gain of 75 µV / e - are extracted from the photon-transfer measurements. The gain characteristics of the avalanche junction are characterized on separate test diodes showing a multiplication factor of 1.6 for red light in frontside illumination.

  5. Transparent, Flexible and Light-Sensitive High Performance Solid-State Supercapacitor

    Science.gov (United States)

    Deka Boruah, Buddha; Maji, Arnab; Misra, Abha

    Supercapacitor, considered as a promising energy storage device because of their additional unique features such as high power density, fast charge-discharge rate, long cycling life, safe operation and low cost, etc. Therefore, recently the rapid development of transparent and flexible supercapacitor is considered as great research challenge. In general, during the fabrication of flexible and transparent supercapacitor, electroactive materials directly transfer on the flexible current collectors or bind the electroactive materials with the current collectors using binder. However, the direct transfer of electrochemically active materials on the current collectors induce higher junction resistance due to weak adhesion. This results in introducing the rapid voltage or capacitance drops during the charging-discharging process of supercapacitors. These issues are resolved by directly growing ZnCo2O4 nanorods (NRs) on flexible indium tin oxide (ITO) coated polyethylene terephthalate (PET) substrates (ZnCo2O4 NRs/ITO) to fabricate transparent, solid-state ITO/ZnCo2O4 NRs//ZnCo2O4 NRs/ITO supercapacitor. Large surface-to-volume ratio of ZnCo2O4 NRs exposes more electrochemically active surface area. The direct growth of ZnCo2O4 NRs on ITO coated PET provides unique ion/charge conduction path and hence excellent ion-diffusion efficiency. Furthermore, fabricated electrodes and the solid-state supercapacitor display the excellent transparency and highly sensitive towards the visible light illumination.

  6. Characterizing high-energy light curves of Fermi/LatGRBs - Oral Presentation

    Energy Technology Data Exchange (ETDEWEB)

    Gillette, Jarred [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-08-23

    A systematic analysis of the light curves of Gamma-Ray Burst (GRBs) with redshift and detected at high-energy (> 100 MeV) by Fermi/LAT has never been done before our work, because there were only a handful of detections. Now we have 20 of those, which we can use to characterize the GRBs in their rest frame. We compared a characteristic decay times Tc of GRBs with redshifts using the new "Pass8" data, and used a Crystal Ball function to parametrize GRB characteristics. An unexpected anti-correlation between Tc and the peak flux was observed. This means that brighter peaked GRBs have shorter durations. There is also no correlation between Tc and the decay index, which is one of the competing hypothesis on the origin of the high-energy emission. We did not observe any bimodality, which is seen in GRBs at lower energies.

  7. Characterizing high-energy light curves of Fermi/Lat GRBs

    Energy Technology Data Exchange (ETDEWEB)

    Gillette, Jarred [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-08-21

    A systematic analysis of the light curves of Gamma-Ray Burst (GRBs) with redshift and detected at high-energy (> 100 MeV) by Fermi/LAT has never been done before our work, because there were only a handful of detections. Now we have 20 of those, which we can use to characterize the GRBs in their rest frame. We compared a characteristic decay times Tc of GRBs with redshifts using the new “Pass 8” data, and used a Crystal Ball function to parametrize GRB characteristics. An unexpected anti-correlation between Tc and the peak flux was observed. This means that brighter peaked GRBs have shorter durations. There is also no correlation between the Tc and the decay index, which makes the anti-correlation with brightness more clear. This results appears to be consistent with the External Shock model, which is one of the competing hypothesis on the origin of the high-energy emission. We did not observe any bimodality, which is seen in GRBs at lower energies.

  8. High-Throughput Multiplex Flow Cytometry Screening for Botulinum Neurotoxin Type A Light Chain Protease Inhibitors

    Science.gov (United States)

    2010-01-01

    Given their medical importance, proteases have been studied by diverse approaches and screened for small molecule protease inhibitors. Here, we present a multiplexed microsphere-based protease assay that uses high-throughput flow cytometry to screen for inhibitors of the light chain protease of botulinum neurotoxin type A (BoNTALC). Our assay uses a full-length substrate and several deletion mutants screened in parallel to identify small molecule inhibitors. The use of multiplex flow cytometry has the advantage of using full-length substrates, which contain already identified distal-binding elements for the BoNTALC, and could lead to a new class of BoNTALC inhibitors. In this study, we have screened 880 off patent drugs and bioavailable compounds to identify ebselen as an in vitro inhibitor of BoNTALC. This discovery demonstrates the validity of our microsphere-based approach and illustrates its potential for high-throughput screening for inhibitors of proteases in general. PMID:20035615

  9. Light regime characterization in an airlift photobioreactor for production of microalgae with high starch content

    OpenAIRE

    Fernandes, Bruno Daniel; Dragone, Giuliano; Teixeira, J. A.; Vicente, A. A.

    2010-01-01

    The slow development of microalgal biotechnology is due to the failure in the design of large-scale photobioreactors (PBRs) where light energy is efficiently utilized. In this work, both the quality and the amount of light reaching a given point of the PBR were determined and correlated with cell density, light path length, and PBR geometry. This was made for two different geometries of the downcomer of an airlift PBR using optical fiber technology that allows to obtain informa...

  10. Slow pupillary light responses in infants at high risk of cerebral palsy were associated with periventricular leukomalacia and neurological outcome

    NARCIS (Netherlands)

    Hamer, E.G.; Vermeulen, R.J.; Dijkstra, L.J.; Hielkema, T.; Kos, C.; Bos, A.F; Hadders-Algra, M.

    2016-01-01

    AIM: Having observed slow pupillary light responses (PLRs) in infants at high risk of cerebral palsy, we retrospectively evaluated whether these were associated with specific brain lesions or unfavourable outcomes. METHODS: We carried out neurological examinations on 30 infants at very high risk of

  11. Slow pupillary light responses in infants at high risk of cerebral palsy were associated with periventricular leukomalacia and neurological outcome

    NARCIS (Netherlands)

    Hamer, Elisa G.; Vermeulen, R. Jeroen; Dijkstra, Linze J.; Hielkema, Tjitske; Kos, Claire; Bos, Arend F.; Hadders-Algra, Mijna

    2016-01-01

    Aim: Having observed slow pupillary light responses (PLRs) in infants at high risk of cerebral palsy, we retrospectively evaluated whether these were associated with specific brain lesions or unfavourable outcomes. Methods: We carried out neurological examinations on 30 infants at very high risk of

  12. Hazards Caused by UV Rays of Xenon Light Based High Performance Solar Simulators.

    Science.gov (United States)

    Dibowski, Gerd; Esser, Kai

    2017-09-01

    Solar furnaces are used worldwide to conduct experiments to demonstrate the feasibility of solar-chemical processes with the aid of concentrated sunlight, or to qualify high temperature-resistant components. In recent years, high-flux solar simulators (HFSSs) based on short-arc xenon lamps are more frequently used. The emitted spectrum is very similar to natural sunlight but with dangerous portions of ultraviolet light as well. Due to special benefits of solar simulators the increase of construction activity for HFSS can be observed worldwide. Hence, it is quite important to protect employees against serious injuries caused by ultraviolet radiation (UVR) in a range of 100 nm to 400 nm. The UV measurements were made at the German Aerospace Center (DLR), Cologne and Paul-Scherrer-Institute (PSI), Switzerland, during normal operations of the HFSS, with a high-precision UV-A/B radiometer using different experiment setups at different power levels. Thus, the measurement results represent UV emissions which are typical when operating a HFSS. Therefore, the biological effects on people exposed to UVR was investigated systematically to identify the existing hazard potential. It should be noted that the permissible workplace exposure limits for UV emissions significantly exceeded after a few seconds. One critical value was strongly exceeded by a factor of 770. The prevention of emissions must first and foremost be carried out by structural measures. Furthermore, unambiguous protocols have to be defined and compliance must be monitored. For short-term activities in the hazard area, measures for the protection of eyes and skin must be taken.

  13. High speed visible light communication using blue GaN laser diodes

    Science.gov (United States)

    Watson, S.; Viola, S.; Giuliano, G.; Najda, S. P.; Perlin, P.; Suski, T.; Marona, L.; Leszczyński, M.; Wisniewski, P.; Czernecki, R.; Targowski, G.; Watson, M. A.; White, H.; Rowe, D.; Laycock, L.; Kelly, A. E.

    2016-10-01

    GaN-based laser diodes have been developed over the last 20 years making them desirable for many security and defence applications, in particular, free space laser communications. Unlike their LED counterparts, laser diodes are not limited by their carrier lifetime which makes them attractive for high speed communication, whether in free space, through fiber or underwater. Gigabit data transmission can be achieved in free space by modulating the visible light from the laser with a pseudo-random bit sequence (PRBS), with recent results approaching 5 Gbit/s error free data transmission. By exploiting the low-loss in the blue part of the spectrum through water, data transmission experiments have also been conducted to show rates of 2.5 Gbit/s underwater. Different water types have been tested to monitor the effect of scattering and to see how this affects the overall transmission rate and distance. This is of great interest for communication with unmanned underwater vehicles (UUV) as the current method using acoustics is much slower and vulnerable to interception. These types of laser diodes can typically reach 50-100 mW of power which increases the length at which the data can be transmitted. This distance could be further improved by making use of high power laser arrays. Highly uniform GaN substrates with low defectivity allow individually addressable laser bars to be fabricated. This could ultimately increase optical power levels to 4 W for a 20-emitter array. Overall, the development of GaN laser diodes will play an important part in free space optical communications and will be vital in the advancement of security and defence applications.

  14. Light regime characterization in an airlift photobioreactor for production of microalgae with high starch content.

    Science.gov (United States)

    Fernandes, Bruno D; Dragone, Giuliano M; Teixeira, José A; Vicente, António A

    2010-05-01

    The slow development of microalgal biotechnology is due to the failure in the design of large-scale photobioreactors (PBRs) where light energy is efficiently utilized. In this work, both the quality and the amount of light reaching a given point of the PBR were determined and correlated with cell density, light path length, and PBR geometry. This was made for two different geometries of the downcomer of an airlift PBR using optical fiber technology that allows to obtain information about quantitative and qualitative aspects of light patterns. This is important since the ability of microalgae to use the energy of photons is different, depending on the wavelength of the radiation. The results show that the circular geometry allows a more efficient light penetration, especially in the locations with a higher radial coordinate (r) when compared to the plane geometry; these observations were confirmed by the occurrence of a higher fraction of illuminated volume of the PBR for this geometry. An equation is proposed to correlate the relative light intensity with the penetration distance for both geometries and different microalgae cell concentrations. It was shown that the attenuation of light intensity is dependent on its wavelength, cell concentration, geometry of PBR, and the penetration distance of light.

  15. High Accuracy Optical Inverse Square Law Experiment Using Inexpensive Light to Frequency Converters

    Science.gov (United States)

    Wanser, Keith H.; Mahrley, Steve; Tanner, Joshua

    2012-01-01

    In this paper we report on the use of two different light to frequency converters, four different light sources, three of which are novel and inexpensive, and a hand held digital multimeter with a frequency counter, suitable for making accurate and rapid determination of the optical inverse square law exponent of -2 to better than [plus or…

  16. Highly efficient absorption of visible and near infrared light in convex gold and nickel grooves

    DEFF Research Database (Denmark)

    Eriksen, René Lynge; Beermann, Jonas; Søndergaard, Thomas

    The realization of nonresonant light absorption with nanostructured metal surfaces by making practical use of nanofocusing optical energy in tapered plasmonic waveguides, is of one of the most fascinating and fundamental phenomena in plasmonics [1,2]. We recently realized broadband light absorpti...

  17. [Effect of high pressure sodium lamp light on color vision in persons with congenital dyschromatopsia].

    Science.gov (United States)

    Trusiewicz, D; Makszewska-Chetnik, Z; Kordalewska, A; Stanioch, W

    1993-01-01

    20 patients with deuteranomaly, protanomaly or protanopia were tested in light of fluorescent and sodium lamp at luminosity about 350 lx and 50 lx. Sodium light increased disturbances in tone vision. moreover, 8 patients mixed up the colours of traffic-signals. These symptoms are considered to be particularly unfavourable for the traffic safety.

  18. Low-frequency wide-field fluorescence lifetime imaging using a high-power near-infrared light-emitting diode light source.

    Science.gov (United States)

    Gioux, Sylvain; Lomnes, Stephen J; Choi, Hak Soo; Frangioni, John V

    2010-01-01

    Fluorescence lifetime imaging (FLi) could potentially improve exogenous near-infrared (NIR) fluorescence imaging, because it offers the capability of discriminating a signal of interest from background, provides real-time monitoring of a chemical environment, and permits the use of several different fluorescent dyes having the same emission wavelength. We present a high-power, LED-based, NIR light source for the clinical translation of wide-field (larger than 5 cm in diameter) FLi at frequencies up to 35 MHz. Lifetime imaging of indocyanine green (ICG), IRDye 800-CW, and 3,3(')-diethylthiatricarbocyanine iodide (DTTCI) was performed over a large field of view (10 cm by 7.5 cm) using the LED light source. For comparison, a laser diode light source was employed as a gold standard. Experiments were performed both on the bench by diluting the fluorescent dyes in various chemical environments in Eppendorf tubes, and in vivo by injecting the fluorescent dyes mixed in Matrigel subcutaneously into CD-1 mice. Last, measured fluorescence lifetimes obtained using the LED and the laser diode sources were compared with those obtained using a state-of-the-art time-domain imaging system and with those previously described in the literature. On average, lifetime values obtained using the LED and the laser diode light sources were consistent, exhibiting a mean difference of 3% from the expected values and a coefficient of variation of 12%. Taken together, our study offers an alternative to laser diodes for clinical translation of FLi and explores the use of relatively low frequency modulation for in vivo imaging.

  19. Design of a High-Power White Light Source with Colloidal Quantum Dots and Non-Rare-Earth Phosphors

    Science.gov (United States)

    Bicanic, Kristopher T.

    This thesis describes the design process of a high-power white light source, using novel phosphor and colloidal quantum dot materials. To incorporate multiple light emitters, we generalized and extended a down-converting layer model. We employed a phosphor mixture comprising of YAG:Ce and K2TiF 6:Mn4+ powders to illustrate the effectiveness of the model. By incorporating experimental photophysical results from the phosphors and colloidal quantum dots, we modeled our system and chose the design suitable for high-power applications. We report a reduction in the correlated color temperature by 600K for phosphor and quantum dot systems, enabling the creation of a warm white light emission at power densities up to 5 kW/cm 2. Furthermore, at this high-power, their emission achieves the digital cinema initiative (DCI) requirements with a luminescence efficacy improvement up to 32% over the stand-alone ceramic YAG:Ce phosphor.

  20. VISAR Validation Test Series at the Light Initiated High Explosive (LIHE) facility.

    Energy Technology Data Exchange (ETDEWEB)

    Covert, Timothy Todd

    2007-02-01

    A velocity interferometer system for any reflector (VISAR) was recently deployed at the light initiated high explosive facility (LIHE) to measure the velocity of an explosively accelerated flyer plate. The velocity data from the flyer plate experiments, using the vendor's fringe constant of 100m/s/fringe, were consistently lower than model predictions. The goal of the VISAR validation test series was to confirm the VISAR system fringe constant. A low velocity gas gun was utilized to impact and accelerate a target at the LIHE facility. VISAR velocity data from the accelerated target was compared against an independent velocity measurement. The data from this test series did in fact reveal the fringe constant was significantly higher than the vendor's specification. The correct fringe constant for the LIHE VISAR system has been determined to be 123 m/s/fringe. The Light Initiated High Explosive (LIHE) facility recently completed a Phase I test series to develop an explosively accelerated flyer plate (X-Flyer). The X-Flyer impulse technique consists of first spraying a thin layer of silver acetylide silver nitrate explosive onto a thin flyer plate. The explosive is then initiated using an intense flash of light. The explosive detonation accelerates the flyer across a small air gap towards the test item. The impact of the flyer with the test item creates a shock pulse and an impulsive load in the test unit. The goal of Phase I of the X-Flyer development series was to validate the technique theory and design process. One of the key parameters that control the shock pulse and impulsive load is the velocity of the flyer at impact. To measure this key parameter, a velocity interferometer system for any reflector (VISAR) was deployed at the LIHE facility. The VISAR system was assembled by Sandia personnel from the Explosive Projects and Diagnostics department. The VISAR was a three leg, push-pull system using a fixed delay cavity. The primary optical components

  1. Study on the Use of Hydride Fuel in High-Performance Light Water Reactor Concept

    Directory of Open Access Journals (Sweden)

    Haileyesus Tsige-Tamirat

    2015-01-01

    Full Text Available Hydride fuels have features which could make their use attractive in future advanced power reactors. The potential benefit of use of hydride fuel in HPLWR without introducing significant modification in the current core design concept of the high-performance light water reactor (HPLWR has been evaluated. Neutronics and thermal hydraulic analyses were performed for a single assembly model of HPLWR with oxide and hydride fuels. The hydride assembly shows higher moderation with softer neutron spectrum and slightly more uniform axial power distribution. It achieves a cycle length of 18 months with sufficient excess reactivity. At Beginning of Cycle the fuel temperature coefficient of the hydride assembly is higher whereas the moderator and void coefficients are lower. The thermal hydraulic results show that the achievable fuel temperature in the hydride assembly is well below the design limits. The potential benefits of the use of hydride fuel in the current design of the HPLWR with the achieved improvements in the core neutronics characteristics are not sufficient to justify the replacement of the oxide fuel. Therefore for a final evaluation of the use of hydride fuels in HPLWR concepts additional studies which include modification of subassembly and core layout designs are required.

  2. Neutronic and Thermal-hydraulic Modelling of High Performance Light Water Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Seppaelae, Malla [VTT Technical Research Centre of Finland, P.O.Box 1000, FI02044 VTT (Finland)

    2008-07-01

    High Performance Light Water Reactor (HPLWR), which is studied in EU project 'HPLWR2', uses water at supercritical pressures as coolant and moderator to achieve higher core outlet temperature and thus higher efficiency compared to present reactors. At VTT Technical Research Centre of Finland, functionality of the thermal-hydraulics in the coupled reactor dynamics code TRAB3D/ SMABRE was extended to supercritical pressures for the analyses of HPLWR. Input models for neutronics and thermal-hydraulics were made for TRAB3D/ SMABRE according to the latest HPLWR design. A preliminary analysis was performed in which the capability of SMABRE in the transition from supercritical pressures to subcritical pressures was demonstrated. Parameterized two-group cross sections for TRAB3D neutronics were received from Hungarian Academy of Sciences KFKI Atomic Energy Research Institute together with a subroutine for handling them. PSG, a new Monte Carlo transport code developed at VTT, was also used to generate two-group constants for HPLWR and comparisons were made with the KFKI cross sections and MCNP calculations. (author)

  3. High-speed spatial frequency domain imaging with temporally modulated light

    Science.gov (United States)

    Applegate, Matthew B.; Roblyer, Darren

    2017-07-01

    Spatial frequency domain imaging (SFDI) is a wide-field diffuse optical technique used to obtain optical properties and chromophore concentrations in highly scattering media, such as biological tissue. Here, we present a method for rapidly acquiring multispectral SFDI data by modulating each illumination wavelength at a different temporal frequency. In the remitted signal, each wavelength is temporally demodulated and processed using conventional SFDI techniques. We demonstrate a proof-of-concept system capable of acquiring wide-field maps (2048×1536 pixels, 8.5×6.4 cm) of optical properties at three wavelengths in under 2.5 s. Data acquired by this method show a good agreement with a commercial SFDI imaging system (with an average error of 13% in absorption and 8% in scattering). Additionally, we show that this strategy is insensitive to ambient lighting conditions, making it more practical for clinical translation. In the future, this technique could be expanded to tens or hundreds of wavelengths without increasing acquisition time.

  4. Lightness perception in high dynamic range images: local and remote luminance effects.

    Science.gov (United States)

    Allred, Sarah R; Radonjic, Ana; Gilchrist, Alan L; Brainard, David H

    2012-02-08

    We measured the perceived lightness of target patches embedded in high dynamic range checkerboards. We independently varied the luminance of checks immediately surrounding the test and those remote from it. The data establish context transfer functions (CTFs) that characterize perceptual matches across checkerboard contexts. Several features of the CTFs are broadly consistent with previous research: Matched luminance decreases when overall context luminance decreases; matched luminance increases when overall context luminance increases; manipulating context locations near the target has a greater effect than manipulating locations far from the target patch. The measured CTFs are not well described, however, by changes with context in multiplicative gain alone or by changes in both multiplicative and subtractive adaptation parameters. We were able to fit the data with a three-parameter model of adaptation. This allowed us to characterize the CTFs by specifying the luminances that appeared white, black, and gray (white point, black point, and gray point, respectively). The white and black points depended additively on the local and remote contrasts, but accounting for the gray point required an interaction term. Analysis of this effect suggests that the target patch itself must be included in a description of the visual context.

  5. Interactive Light Stimulus Generation with High Performance Real-Time Image Processing and Simple Scripting

    Directory of Open Access Journals (Sweden)

    László Szécsi

    2017-12-01

    Full Text Available Light stimulation with precise and complex spatial and temporal modulation is demanded by a series of research fields like visual neuroscience, optogenetics, ophthalmology, and visual psychophysics. We developed a user-friendly and flexible stimulus generating framework (GEARS GPU-based Eye And Retina Stimulation Software, which offers access to GPU computing power, and allows interactive modification of stimulus parameters during experiments. Furthermore, it has built-in support for driving external equipment, as well as for synchronization tasks, via USB ports. The use of GEARS does not require elaborate programming skills. The necessary scripting is visually aided by an intuitive interface, while the details of the underlying software and hardware components remain hidden. Internally, the software is a C++/Python hybrid using OpenGL graphics. Computations are performed on the GPU, and are defined in the GLSL shading language. However, all GPU settings, including the GPU shader programs, are automatically generated by GEARS. This is configured through a method encountered in game programming, which allows high flexibility: stimuli are straightforwardly composed using a broad library of basic components. Stimulus rendering is implemented solely in C++, therefore intermediary libraries for interfacing could be omitted. This enables the program to perform computationally demanding tasks like en-masse random number generation or real-time image processing by local and global operations.

  6. A 3-D high accuracy positioning system based on visible light communication with novel positioning algorithm

    Science.gov (United States)

    Zheng, Huanhuan; Xu, Zhaowen; Yu, Changyuan; Gurusamy, Mohan

    2017-08-01

    A novel indoor positioning system (IPS) with high positioning precision, based on visible light communication (VLC), is proposed and demonstrated with the dimensions of 100 cm×118.5 cm×128.7 cm. The average positioning distance error is 1.72 cm using the original 2-D positioning algorithm. However, at the corners of the test-bed, the positioning errors are relatively larger than other places. Thus, an error correcting algorithm (ECA) is applied at the corners in order to improve the positioning accuracy. The average positioning errors of four corners decrease from 3.67 cm to 1.55 cm. Then, a 3-D positioning algorithm is developed and the average positioning error of 1.90 cm in space is achieved. Four altitude levels are chosen and on each receiver plane with different heights, four points are picked up to test the positioning error. The average positioning errors in 3-D space are all within 3 cm on these four levels and the performance on each level is similar. A random track is also drawn to show that in 3-D space, the positioning error of random point is within 3 cm.

  7. Highly polarized light from stable ordered magnetic fields in GRB 120308A.

    Science.gov (United States)

    Mundell, C G; Kopač, D; Arnold, D M; Steele, I A; Gomboc, A; Kobayashi, S; Harrison, R M; Smith, R J; Guidorzi, C; Virgili, F J; Melandri, A; Japelj, J

    2013-12-05

    After the initial burst of γ-rays that defines a γ-ray burst (GRB), expanding ejecta collide with the circumburst medium and begin to decelerate at the onset of the afterglow, during which a forward shock travels outwards and a reverse shock propagates backwards into the oncoming collimated flow, or 'jet'. Light from the reverse shock should be highly polarized if the jet's magnetic field is globally ordered and advected from the central engine, with a position angle that is predicted to remain stable in magnetized baryonic jet models or vary randomly with time if the field is produced locally by plasma or magnetohydrodynamic instabilities. Degrees of linear polarization of P ≈ 10 per cent in the optical band have previously been detected in the early afterglow, but the lack of temporal measurements prevented definitive tests of competing jet models. Hours to days after the γ-ray burst, polarization levels are low (P GRBs contain magnetized baryonic jets with large-scale uniform fields that can survive long after the initial explosion.

  8. Highly efficient visible light mediated azo dye degradation through barium titanate decorated reduced graphene oxide sheets

    Science.gov (United States)

    Rastogi, Monisha; Kushwaha, H. S.; Vaish, Rahul

    2016-03-01

    This study investigates BaTiO3 decorated reduced graphene oxide sheets as a potential visible light active catalyst for dye degradation (Rhodamine B). The composites were prepared through conventional hydrothermal synthesis technique using hydrazine as a reducing agent. A number of techniques have been employed to affirm the morphology, composition and photocatalytic properties of the composites; these include UV-visible spectrophotoscopy that assisted in quantifying the concentration difference of Rhodamine B. The phase homogeneity of the composites was examined through x-ray powder diffraction (XRD) and high resolution transmission electron microscopy (HRTEM) was employed to confirm the orientation of the BaTiO3 particles over the reduced graphene oxide sheets. Photoluminescence (PL) emission spectra assisted in determining the surface structure and excited state of the catalyst. Fourier transformed-infrared (FTIR) spectra investigated the vibrations and adsorption peak of the composites, thereby ascertaining the formation of reduced graphene oxide. In addition, diffuse reflectance spectroscopy (DRS) demonstrated an enhanced absorption in the visible region. The experimental investigations revealed that graphene oxide acted as charge collector and simultaneously facilitated surface adsorption and photo-sensitization. It could be deduced that BaTiO3-reduced graphene oxide composites are of significant interest the field of water purification through solar photocatalysis. [Figure not available: see fulltext.

  9. A new high dynamic range ROIC with smart light intensity control unit

    Science.gov (United States)

    Yazici, Melik; Ceylan, Omer; Shafique, Atia; Abbasi, Shahbaz; Galioglu, Arman; Gurbuz, Yasar

    2017-05-01

    This journal presents a new high dynamic range ROIC with smart pixel which consists of two pre-amplifiers that are controlled by a circuit inside the pixel. Each pixel automatically decides which pre-amplifier is used according to the incoming illumination level. Instead of using single pre-amplifier, two input pre-amplifiers, which are optimized for different signal levels, are placed inside each pixel. The smart circuit mechanism, which decides the best input circuit according to the incoming light level, is also designed for each pixel. In short, an individual pixel has the ability to select the best input amplifier circuit that performs the best/highest SNR for the incoming signal level. A 32 × 32 ROIC prototype chip is designed to demonstrate the concept in 0.18 μ m CMOS technology. The prototype is optimized for NIR and SWIR bands. Instead of a detector, process variation optimized current sources are placed inside the ROIC. The chip achieves minimum 8.6 e- input referred noise and 98.9 dB dynamic range. It has the highest dynamic range in the literature in terms of analog ROICs for SWIR band. It is operating in room temperature and power consumption is 2.8 μ W per pixel.

  10. High-power green light generation by second harmonic generation of single-frequency tapered diode lasers

    DEFF Research Database (Denmark)

    Jensen, Ole Bjarlin; Andersen, Peter E.; Sumpf, Bernd

    2010-01-01

    laser emits in excess of 9 W single-frequency output power with a good beam quality. The output from the tapered diode laser is frequency doubled using periodically poled MgO:LiNbO3. We investigate the modulation potential of the green light and improve the modulation depth from 1:4 to 1:50.......We demonstrate the generation of high power (>1.5W) and single-frequency green light by single-pass second harmonic generation of a high power tapered diode laser. The tapered diode laser consists of a DBR grating for wavelength selectivity, a ridge section and a tapered section. The DBR tapered...

  11. Hydraulic analysis of a backflow limiter for the high performance light water reactor

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, K. [EnBW Kernkraft GmbH, Philippsburg (Germany). Kernkraftwerk Philippsburg; Laurien, E. [Stuttgart Univ. (Germany). Inst. for Nuclear Energy and Energy Systems; Class, A.G.; Schulenberg, T. [Forschungszentrum Karlsruhe (Germany)

    2008-07-01

    The high performance light water reactor (HPLWR) is one of the six concepts of the Generation IV program. It develops current light water reactor technologies and combines them with those of supercritical fossil fired power plants, using a once-through direct steam cycle. Water is used both as moderator and as coolant and flows as a single phase fluid through the core at a supercritical pressure of 25 MPa. The coolant exits with temperatures around 500 C. A conceptual design of the RPV and its internals has been presented by Fischer et al (2006). It features four circumferentially arranged inlets which are placed well above the four outlets. As recirculation pumps will not be required for this concept, a postulated break of one of the inlet feedwater lines will cause an immediate loss of flow and reduce the available water inventory in the vessel to cool the core. The following temperature peak can be reduced significantly if an additional safety component is installed in the feedwater lines to control and minimize this outflow until further steps are executed in order to maintain a reasonable amount of water inside the vessel to cool the core. The design of the backflow limiter features 10 inlet swirler vanes with an angle of 10 deg and 30 exit swirler vanes with an angle of 60 deg, the swirl chamber has an overall diameter of 0.95 m. The component fits inside the inlet flange and is therefore protected against damage from the outside. In case of a loss of coolant accident (LOCA), e.g. in case of a postulated break of one of the four inlet feedwater lines, the backflow limiter is able to reduce the mass flow for normal operation in reverse direction by a factor of approximately 5. Further work will include a sensitivity-study of the applied mesh and a comparison of the k-w SST turbulence model to non-linear RANS models, since the prediction of swirl flow is rather imprecise using the isotropic models.

  12. Quantitative neuroanatomy of all Purkinje cells with light sheet microscopy and high-throughput image analysis

    Directory of Open Access Journals (Sweden)

    Ludovico eSilvestri

    2015-05-01

    Full Text Available Characterizing the cytoarchitecture of mammalian central nervous system on a brain-wide scale is becoming a compelling need in neuroscience. For example, realistic modeling of brain activity requires the definition of quantitative features of large neuronal populations in the whole brain. Quantitative anatomical maps will also be crucial to classify the cytoarchtitectonic abnormalities associated with neuronal pathologies in a high reproducible and reliable manner. In this paper, we apply recent advances in optical microscopy and image analysis to characterize the spatial distribution of Purkinje cells across the whole cerebellum. Light sheet microscopy was used to image with micron-scale resolution a fixed and cleared cerebellum of an L7-GFP transgenic mouse, in which all Purkinje cells are fluorescently labeled. A fast and scalable algorithm for fully automated cell identification was applied on the image to extract the position of all the fluorescent Purkinje cells. This vectorized representation of the cell population allows a thorough characterization of the complex three-dimensional distribution of the neurons, highlighting the presence of gaps inside the lamellar organization of Purkinje cells, whose density is believed to play a significant role in autism spectrum disorders. Furthermore, clustering analysis of the localized somata permits dividing the whole cerebellum in groups of Purkinje cells with high spatial correlation, suggesting new possibilities of anatomical partition. The quantitative approach presented here can be extended to study the distribution of different types of cell in many brain regions and across the whole encephalon, providing a robust base for building realistic computational models of the brain, and for unbiased morphological tissue screening in presence of pathologies and/or drug treatments.

  13. High color rendering index white organic light-emitting diode using levofloxacin as blue emitter

    Science.gov (United States)

    Miao, Yan-Qin; Gao, Zhi-Xiang; Zhang, Ai-Qin; Li, Yuan-Hao; Wang, Hua; Jia, Hu-Sheng; Liu, Xu-Guang; Tsuboi, Taijuf

    2015-05-01

    Levofloxacin (LOFX), which is well-known as an antibiotic medicament, was shown to be useful as a 452-nm blue emitter for white organic light-emitting diodes (OLEDs). In this paper, the fabricated white OLED contains a 452-nm blue emitting layer (thickness of 30 nm) with 1 wt% LOFX doped in CBP (4,4’-bis(carbazol-9-yl)biphenyl) host and a 584-nm orange emitting layer (thickness of 10 nm) with 0.8 wt% DCJTB (4-(dicyanomethylene)-2-tert-butyl-6-(1,1,7,7-tetramethyljulolidin-4-yl-vinyl)-4H-pyran) doped in CBP, which are separated by a 20-nm-thick buffer layer of TPBi (2,2’,2”-(benzene-1,3,5-triyl)-tri(1-phenyl-1H-benzimidazole). A high color rendering index (CRI) of 84.5 and CIE chromaticity coordinates of (0.33, 0.32), which is close to ideal white emission CIE (0.333, 0.333), are obtained at a bias voltage of 14 V. Taking into account that LOFX is less expensive and the synthesis and purification technologies of LOFX are mature, these results indicate that blue fluorescence emitting LOFX is useful for applications to white OLEDs although the maximum current efficiency and luminance are not high. The present paper is expected to become a milestone to using medical drug materials for OLEDs. Project supported by the Program for New Century Excellent Talents in University of Ministry of Education of China (Grant No. NCET-13-0927), the International Science & Technology Cooperation Program of China (Grant No. 2012DFR50460), the National Natural Science Foundation of China (Grant Nos. 21101111 and 61274056), and the Shanxi Provincial Key Innovative Research Team in Science and Technology, China (Grant No. 2012041011).

  14. Analysis of Environmental Effects on Leaf Temperature under Sunlight, High Pressure Sodium and Light Emitting Diodes.

    Science.gov (United States)

    Nelson, Jacob A; Bugbee, Bruce

    2015-01-01

    The use of LED technology is commonly assumed to result in significantly cooler leaf temperatures than high pressure sodium technology. To evaluate the magnitude of this effect, we measured radiation incident to and absorbed by a leaf under four radiation sources: clear sky sunlight in the field, sunlight in a glass greenhouse, and indoor plants under either high pressure sodium or light emitting diodes. We then applied a common mechanistic energy-balance model to compare leaf to air temperature difference among the radiation sources and environments. At equal photosynthetic photon flux, our results indicate that the effect of plant water status and leaf evaporative cooling is much larger than the effect of radiation source. If plants are not water stressed, leaves in all four radiation sources were typically within 2°C of air temperature. Under clear sky conditions, cool sky temperatures mean that leaves in the field are always cooler than greenhouse or indoor plants-when photosynthetic photon flux, stomatal conductance, wind speed, vapor pressure deficit, and leaf size are equivalent. As water stress increases and cooling via transpiration decreases, leaf temperatures can increase well above air temperature. In a near-worst case scenario of water stress and low wind, our model indicates that leaves would increase 6°, 8°, 10°, and 12°C above air temperature under field, LED, greenhouse, and HPS scenarios, respectively. Because LED fixtures emit much of their heat through convection rather than radiative cooling, they result in slightly cooler leaf temperatures than leaves in greenhouses and under HPS fixtures, but the effect of LED technology on leaf temperature is smaller than is often assumed. Quantifying the thermodynamic outputs of these lamps, and their physiological consequences, will allow both researchers and the horticulture industry to make informed decisions when employing these technologies.

  15. Analysis of Environmental Effects on Leaf Temperature under Sunlight, High Pressure Sodium and Light Emitting Diodes.

    Directory of Open Access Journals (Sweden)

    Jacob A Nelson

    Full Text Available The use of LED technology is commonly assumed to result in significantly cooler leaf temperatures than high pressure sodium technology. To evaluate the magnitude of this effect, we measured radiation incident to and absorbed by a leaf under four radiation sources: clear sky sunlight in the field, sunlight in a glass greenhouse, and indoor plants under either high pressure sodium or light emitting diodes. We then applied a common mechanistic energy-balance model to compare leaf to air temperature difference among the radiation sources and environments. At equal photosynthetic photon flux, our results indicate that the effect of plant water status and leaf evaporative cooling is much larger than the effect of radiation source. If plants are not water stressed, leaves in all four radiation sources were typically within 2°C of air temperature. Under clear sky conditions, cool sky temperatures mean that leaves in the field are always cooler than greenhouse or indoor plants-when photosynthetic photon flux, stomatal conductance, wind speed, vapor pressure deficit, and leaf size are equivalent. As water stress increases and cooling via transpiration decreases, leaf temperatures can increase well above air temperature. In a near-worst case scenario of water stress and low wind, our model indicates that leaves would increase 6°, 8°, 10°, and 12°C above air temperature under field, LED, greenhouse, and HPS scenarios, respectively. Because LED fixtures emit much of their heat through convection rather than radiative cooling, they result in slightly cooler leaf temperatures than leaves in greenhouses and under HPS fixtures, but the effect of LED technology on leaf temperature is smaller than is often assumed. Quantifying the thermodynamic outputs of these lamps, and their physiological consequences, will allow both researchers and the horticulture industry to make informed decisions when employing these technologies.

  16. Two-dimensional artificial light-harvesting antennae with predesigned high-order structure and robust photosensitising activity

    Science.gov (United States)

    Feng, Xiao; Ding, Xuesong; Chen, Long; Wu, Yang; Liu, Lili; Addicoat, Matthew; Irle, Stephan; Dong, Yuping; Jiang, Donglin

    2016-09-01

    Highly ordered discrete assemblies of chlorophylls that are found in natural light-harvesting antennae are key to photosynthesis, which converts light energy to chemical energy and is the principal producer of organic matter on Earth. Porphyrins and phthalocyanines, which are analogues of chlorophylls, exhibit a strong absorbance of visible and near-infrared light, respectively. A highly ordered porphyrin-co-phthalocyanine antennae would harvest photons over the entire solar spectrum for chemical transformation. However, such a robust antennae has not yet been synthesised. Herein, we report a strategy that merges covalent bonds and noncovalent forces to produce highly ordered two-dimensional porphyrin-co-phthalocyanine antennae. This methodology enables control over the stoichiometry and order of the porphyrin and phthalocyanine units; more importantly, this approach is compatible with various metalloporphyrin and metallophthalocyanine derivatives and thus may lead to the generation of a broad structural diversity of two-dimensional artificial antennae. These ordered porphyrin-co-phthalocyanine two-dimensional antennae exhibit unique optical properties and catalytic functions that are not available with single-component or non-structured materials. These 2D artificial antennae exhibit exceptional light-harvesting capacity over the entire solar spectrum as a result of a synergistic light-absorption effect. In addition, they exhibit outstanding photosensitising activities in using both visible and near-infrared photons for producing singlet oxygen.

  17. High iron requirement for growth, photosynthesis, and low-light acclimation in the coastal cyanobacterium Synechococcus bacillaris

    Directory of Open Access Journals (Sweden)

    William eSunda

    2015-06-01

    Full Text Available Iron limits carbon fixation in much of the modern ocean due to the very low solubility of ferric iron in oxygenated ocean waters. We examined iron limitation of growth rate under varying light intensities in the coastal cyanobacterium Synechococcus bacillaris, a descendent of the oxygenic phototrophs that evolved ca. 3 billion years ago when the ocean was reducing and iron was present at much higher concentrations as soluble Fe(II. Decreasing light intensity increased the cellular iron:carbon (Fe:C ratio needed to support a given growth rate, indicating that iron and light may co-limit the growth of Synechococcus in the ocean, as shown previously for eukaryotic phytoplankton. The cellular Fe:C ratios needed to support a given growth rate were 5- to 8-fold higher than ratios for coastal eukaryotic algae growing under the same light conditions. The higher iron requirements for growth in the coastal cyanobacterium may be largely caused by the high demand for iron in photosynthesis, and to higher ratios of iron-rich photosystem I to iron-poor photosystem II in Synechococcus than in eukaryotic algae. This high iron requirement may also be vestigial and represent an adaptation to the much higher iron levels in the ancient reducing ocean. Due to the high cellular iron requirement for photosynthesis and growth, and for low light acclimation, Synechococcus may be excluded from many low-iron and low-light environments. Indeed, it decreases rapidly with depth within the ocean’s deep chlorophyll maximum (DCM where iron and light levels are low, and lower-iron requiring picoeukaryotes typically dominate the biomass of phytoplankton community within the mid to lower DCM.

  18. High iron requirement for growth, photosynthesis, and low-light acclimation in the coastal cyanobacterium Synechococcus bacillaris.

    Science.gov (United States)

    Sunda, William G; Huntsman, Susan A

    2015-01-01

    Iron limits carbon fixation in much of the modern ocean due to the very low solubility of ferric iron in oxygenated ocean waters. We examined iron-limitation of growth rate under varying light intensities in the coastal cyanobacterium Synechococcus bacillaris, a descendent of the oxygenic phototrophs that evolved ca. 3 billion years ago when the ocean was reducing and iron was present at much higher concentrations as soluble Fe(II). Decreasing light intensity increased the cellular iron:carbon (Fe:C) ratio needed to support a given growth rate, indicating that iron and light may co-limit the growth of Synechococcus in the ocean, as shown previously for eukaryotic phytoplankton. The cellular Fe:C ratios needed to support a given growth rate were 5- to 8-fold higher than ratios for coastal eukaryotic algae growing under the same light conditions. The higher iron requirements for growth in the coastal cyanobacterium may be largely caused by the high demand for iron in photosynthesis, and to higher ratios of iron-rich photosystem I to iron-poor photosystem II in Synechococcus than in eukaryotic algae. This high iron requirement may also be vestigial and represent an adaptation to the much higher iron levels in the ancient reducing ocean. Due to the high cellular iron requirement for photosynthesis and growth, and for low light acclimation, Synechococcus may be excluded from many low-iron and low-light environments. Indeed, it decreases rapidly with depth within the ocean's deep chlorophyll maximum (DCM) where iron and light levels are low, and lower-iron requiring picoeukaryotes typically dominate the biomass of phytoplankton community within the mid to lower DCM.

  19. Ultrabroad linewidth orange-emitting nanowires LED for high CRI laser-based white lighting and gigahertz communications

    KAUST Repository

    Janjua, Bilal

    2016-08-10

    Group-III-nitride laser diode (LD)-based solid-state lighting device has been demonstrated to be droop-free compared to light-emitting diodes (LEDs), and highly energy-efficient compared to that of the traditional incandescent and fluorescent white light systems. The YAG:Ce3+ phosphor used in LD-based solid-state lighting, however, is associated with rapid degradation issue. An alternate phosphor/LD architecture, which is capable of sustaining high temperature, high power density, while still intensity- and bandwidth-tunable for high color-quality remained unexplored. In this paper, we present for the first time, the proof-of-concept of the generation of high-quality white light using an InGaN-based orange nanowires (NWs) LED grown on silicon, in conjunction with a blue LD, and in place of the compound-phosphor. By changing the relative intensities of the ultrabroad linewidth orange and narrow-linewidth blue components, our LED/LD device architecture achieved correlated color temperature (CCT) ranging from 3000 K to above 6000K with color rendering index (CRI) values reaching 83.1, a value unsurpassed by the YAG-phosphor/blue-LD counterpart. The white-light wireless communications was implemented using the blue LD through on-off keying (OOK) modulation to obtain a data rate of 1.06 Gbps. We therefore achieved the best of both worlds when orange-emitting NWs LED are utilized as “active-phosphor”, while blue LD is used for both color mixing and optical wireless communications.

  20. High Performance and Energy Efficient Traffic Light Controller Design Using FPGA

    DEFF Research Database (Denmark)

    Pandey, Sujeet; Shrivastav, Vivek Kumar; Sharma, Rashmi

    2017-01-01

    In this work, Verilog is used as hardware description language for implementation of traffic light controller. It shows Red, Green and Yellow color at a predefined interval. Technology scaling is used as energy efficient technique. We have used 90nm, 65nm, 40nm and 28nm technology based FPGA...... and then we have analyzed power consumption for traffic light controller on different FPGA. Leakage power is in range of 97.5-99% of total power consumption by traffic light controller on Virtex-7 FPGA. Signal power, clock power and IOs power are almost negligible. Power dissipation is measured on XPOWER...

  1. High Iron Requirement for Growth, Photosynthesis, and Low-light Acclimation in the Marine Cyanobacterium Synechococcus bacillaris

    Science.gov (United States)

    Sunda, W. G.; Huntsman, S. A.

    2016-02-01

    Iron is a critical nutrient in photosynthesis and limits phytoplankton growth in large regions of the ocean. Most of the iron in phytoplankton occurs in iron-containing proteins in the photosynthetic apparatus, and thus interactions among cellular iron, light, and growth rate are predicted. In agreement with this prediction, decreasing light intensity increased the cellular iron:carbon (Fe:C) ratio needed to support a given growth rate by 2- to 3-fold in both a coastal diatom Thalassiosira pseudonana, and a coastal cyanobacterium Synechococcus bacillaris due to an increase in iron-containing photosynthetic units. However, although the light responses were similar, the cellular Fe:C ratios needed to support a given growth rate were 5- to 8-fold higher in the cyanobacterium than in the diatom, a pattern seen in other Syechococcus isolates and eukaryotic phytoplankton. Due to the high iron requirement for growth and low light acclimation, we might expect Synechococcus to be at a competitive disadvantage in many low-iron and low-light environments. Indeed, it decreases rapidly with depth within the ocean's deep chlorophyll maximum (DCM), where iron and light levels are low and lower-iron requiring eukaryotic algae typically dominate the phytoplankton biomass in the mid to lower DCM.

  2. High-performance slow light photonic crystal waveguides with topology optimized or circular-hole based material layouts

    DEFF Research Database (Denmark)

    Wang, Fengwen; Jensen, Jakob Søndergaard; Sigmund, Ole

    2012-01-01

    energy located in air regions. It is demonstrated that slow light with a group index up to ng=278 can be achieved by topology optimized waveguides with promising modal confinement and restricted group-velocity-dispersion. All the topology optimized waveguides achieve a normalized group-index bandwidth......Photonic crystal waveguides are optimized for modal confinement and loss related to slow light with high group index. A detailed comparison between optimized circular-hole based waveguides and optimized waveguides with free topology is performed. Design robustness with respect to manufacturing...... imperfections is enforced by considering different design realizations generated from under-, standard- and over-etching processes in the optimization procedure. A constraint ensures a certain modal confinement, and loss related to slow light with high group index is indirectly treated by penalizing field...

  3. Luminescent carbon quantum dots with high quantum yield as a single white converter for white light emitting diodes

    Energy Technology Data Exchange (ETDEWEB)

    Feng, X. T.; Zhang, Y.; Liu, X. G., E-mail: liuxuguang@tyut.edu.cn [Key Laboratory of Interface Science and Engineering in Advanced Materials, Taiyuan University of Technology, Taiyuan 030024 (China); College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Zhang, F.; Wang, Y. L.; Yang, Y. Z., E-mail: yyztyut@126.com [Key Laboratory of Interface Science and Engineering in Advanced Materials, Taiyuan University of Technology, Taiyuan 030024 (China); Research Center on Advanced Materials Science and Technology, Taiyuan University of Technology, Taiyuan 030024 (China)

    2015-11-23

    Carbon quantum dots (CQDs) with high quantum yield (51.4%) were synthesized by a one-step hydrothermal method using thiosalicylic acid and ethylenediamine as precursor. The CQDs have the average diameter of 2.3 nm and possess excitation-independent emission wavelength in the range from 320 to 440 nm excitation. Under an ultraviolet (UV) excitation, the CQDs aqueous solutions emit bright blue fluorescence directly and exhibit broad emission with a high spectral component ratio of 67.4% (blue to red intensity to total intensity). We applied the CQDs as a single white-light converter for white light emitting diodes (WLEDs) using a UV-LED chip as the excitation light source. The resulted WLED shows superior performance with corresponding color temperature of 5227 K and the color coordinates of (0.34, 0.38) belonging to the white gamut.

  4. Highly efficient inverted polymer light-emitting diodes using surface modifications of ZnO layer

    National Research Council Canada - National Science Library

    Lee, Bo Ram; Jung, Eui Dae; Park, Ji Sun; Nam, Yun Seok; Min, Sa Hoon; Kim, Byeong-Su; Lee, Kyung-Min; Jeong, Jong-Ryul; Friend, Richard H; Kim, Ji-Seon; Kim, Sang Ouk; Song, Myoung Hoon

    2014-01-01

    .... Here, we improve the efficiency of inverted polymer light-emitting diodes by introducing a spontaneously formed ripple-shaped nanostructure of ZnO and applying an amine-based polar solvent treatment...

  5. Study of halo nuclei breakup on light targets at intermediate and high energies

    CERN Document Server

    Parfenova, Ioulia

    2002-01-01

    The study of exotic nuclei is one of the most important topics in modern nuclear physics. It allows general understanding of the structure and nature of light nuclear systems in the vicinity of the driplines. Most of the leading facilities in the world, CERN, GANIL, GSI in Europe, RIKEN in Japan, and NSCL(MSU) in USA, are involved in these investigations. Recently, new experimental data on the properties of light halo nuclei such as extremely large interaction cross sections, huge electromagnetic dissociation cross sections, narrow momentum distribution of fragments from breakup reactions, unusual modes of the beta-decay of these nuclei on the borders of the stability, were obtained. This Thesis is based on a series of articles devoted to theoretical investigations of nuclear breakup reactions with light halo nuclei at intermediate energies impinging on light target nuclei. Special attention is paid to the question of sensitivity of the calculated breakup cross sections and longitudinal momentum distributions...

  6. CONSIDERATION OF THE IMPACT OF HIGH HARMONICS WHEN SELECTING THE CONDUCTOR CROSS-SECTIONS OF LINES OF OUTDOOR LIGHTING

    Directory of Open Access Journals (Sweden)

    V. B. Kozlovskaya

    2017-01-01

    Full Text Available The operating mode of the lighting line depends on the correct choice of conductor cross section. The magnitude of the cross section has an influence on the provision of the required voltage levels on the light sources. The choice of the conductor cross section has been fulfilled based on calculations of the operating mode of the standard line of outdoor lighting specified in the article. Luminaries with high pressure sodium lamps connected through electromagnetic ballasts were used as sources of light. When choosing the conductor cross section of light lines a number of simplifications are commonly used. Attention is paid to the choice of sections without such assumptions: the inductive resistance of conductors is taken into account; the power of the luminaire depends on the voltage level in it. Luminaries with high pressure sodium lamps are the sources of high harmonics. Three variants of calculation are demonstrated depending on the accounting (or non-accounting of high odd harmonics. The methods of calculating the mode of the lighting line are also presented in the article. The calculation is performed with the aid of Mathcad software. Operating parameters for each phase of the line (i.e. voltage in the items of the scheme, power, currents, power, and voltage losses in all the sections were determined. The diagrams of the voltage distribution at items of the lighting line for three variants of calculation are plotted for various sections of aluminum conductors. On this basis the choice of the optimum magnitude of the conductor cross section of the lighting line was made. The obtained results of different calculation variants are compared. The comparison of the results obtained with the use of various methods of calculation was made. The impact of high harmonics on the operating mode of the line under consideration has been analyzed. The presence of high harmonics causes an increase of voltage losses, the distortion of sinusoidal voltage. The

  7. Highly sensitive covalently functionalized light-addressable potentiometric sensor for determination of biomarker

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Jintao [School of Life and Environmental Sciences, Guilin University of Electronic Technology, Guilin, Guangxi 541004 (China); Guangxi Experiment Center of Information Sciences, Guilin University of Electronic Technology, Guilin, Guangxi 541004 (China); Guan, Mingyuan; Huang, Guoyin; Qiu, Hengming; Chen, Zhengcheng [School of Life and Environmental Sciences, Guilin University of Electronic Technology, Guilin, Guangxi 541004 (China); Li, Guiyin, E-mail: liguiyin01@163.com [School of Life and Environmental Sciences, Guilin University of Electronic Technology, Guilin, Guangxi 541004 (China); Guangxi Experiment Center of Information Sciences, Guilin University of Electronic Technology, Guilin, Guangxi 541004 (China); Huang, Yong, E-mail: huangyong503@126.com [School of Life and Environmental Sciences, Guilin University of Electronic Technology, Guilin, Guangxi 541004 (China); Guangxi Experiment Center of Information Sciences, Guilin University of Electronic Technology, Guilin, Guangxi 541004 (China)

    2016-06-01

    A biomarker is related to the biological status of a living organism and shows great promise for the early prediction of a related disease. Herein we presented a novel structured light-addressable potentiometric sensor (LAPS) for the determination of a model biomarker, human immunoglobulin G (hIgG). In this system, the goat anti-human immunoglobulin G antibody was used as recognition element and covalently immobilized on the surface of light-addressable potentiometric sensor chip to capture human immunoglobulin G. Due to the light addressable capability of light-addressable potentiometric sensor, human immunoglobulin G dissolved in the supporting electrolyte solution can be detected by monitoring the potential shifts of the sensor. In order to produce a stable photocurrent, the laser diode controlled by field-programmable gate array was used as the light emitter to drive the light-addressable potentiometric sensor. A linear correlation between the potential shift response and the concentration of human immunoglobulin G was achieved and the corresponding regression equation was ΔV (V) = 0.00714C{sub hIgG} (μg/mL)–0.0147 with a correlation coefficient of 0.9968 over a range 0–150 μg/mL. Moreover, the light-addressable potentiometric sensor system also showed acceptable stability and reproducibility. All the results demonstrated that the system was more applicable to detection of disease biomarkers with simple operation, multiple-sample format and might hold great promise in various environmental, food, and clinical applications. - Highlights: • A novel structured light-addressable potentiometric sensor (LAPS) based on covalently functionalized membrane was designed. • The composition of the surface of LAPS chip was investigated by X-ray photoelectron spectroscopy (XPS). • hIgG dissolved in the supporting electrolyte solution can be detected by monitoring the potential shifts of LAPS.

  8. Customized patterned substrates for highly versatile correlative light-scanning electron microscopy

    Science.gov (United States)

    Benedetti, Lorena; Sogne, Elisa; Rodighiero, Simona; Marchesi, Davide; Milani, Paolo; Francolini, Maura

    2014-01-01

    Correlative light electron microscopy (CLEM) combines the advantages of light and electron microscopy, thus making it possible to follow dynamic events in living cells at nanometre resolution. Various CLEM approaches and devices have been developed, each of which has its own advantages and technical challenges. We here describe our customized patterned glass substrates, which improve the feasibility of correlative fluorescence/confocal and scanning electron microscopy. PMID:25391455

  9. LED surgical lighting system with multiple free-form surfaces for highly sterile operating theater application.

    Science.gov (United States)

    Liu, Peng; Zhang, Yaqin; Zheng, Zhenrong; Li, Haifeng; Liu, Xu

    2014-06-01

    Although the ventilation system is widely employed in the operating theater, a strictly sterile surgical environment still cannot be ensured because of laminar disturbance, which is mainly caused by the surgical lighting system. Abandoning traditional products, we propose an LED surgical lighting system, which can alleviate the laminar disturbance and provide an appropriate lighting condition for surgery. It contains a certain amount of LED lens units, which are embedded in the ceiling and arranged around the air supply smallpox. The LED lens unit integrated with an LED light source and a free-form lens is required to produce a uniform circular illumination with a large tolerance to the change of lighting distance. To achieve such a dedicated lens, two free-form refractive surfaces, which are converted into two ordinary differential equations by the design method presented in this paper, are used to deflect the rays. The results show that the LED surgical lighting system can provide an excellent illumination environment for surgery, and, apparently, the laminar disturbance also can be relieved.

  10. Blue light differentially represses mesophyll conductance in high vs low latitude genotypes of Populus trichocarpa Torr. & Gray.

    Science.gov (United States)

    Momayyezi, Mina; Guy, Robert D

    2017-06-01

    To explore what role chloroplast positioning might have in relation to latitudinal variation in mesophyll conductance (gm) of Populus trichocarpa Torr. & Gray (black cottonwood), we examined photosynthetic response to different blue light treatments in six representative genotypes (three northern and three southern). The proportion of blue (B) to red light was varied from 0:100, 10:90, 20:80, 40:60, and 60:40 while keeping the total photosynthetic photon flux density constant. Mesophyll conductance was estimated by monitoring chlorophyll fluorescence in combination with gas exchange. Compared to the control (10% B), gm was significantly lower with increasing blue light. Consistent with a change in chloroplast positioning, there was a simultaneous but reversible decrease in chlorophyll content index (CCI), as measured by foliar greenness, while the extracted, actual chlorophyll content (ACC) remained unchanged. Blue-light-induced decreases in gm and CCI were greater in northern genotypes than in southern genotypes, both absolutely and proportionally, consistent with their inherently higher photosynthetic rate. Treatment of leaves with cytochalasin D, an inhibitor of actin-based chloroplast motility, reduced both CCI and ACC but had no effect on the CCI/ACC ratio and fully blocked any effect of blue light on CCI. Cytochalasin D reduced gm by ∼56% under 10% B, but did not block the effect of 60% B on gm, which was reduced a further 20%. These results suggest that the effect of high blue light on gm is at least partially independent of chloroplast repositioning. High blue light reduced carbonic anhydrase activity by 20% (P<0.05), consistent with a possible reduction in protein-mediated facilitation of CO2 diffusion. Copyright © 2017 Elsevier GmbH. All rights reserved.

  11. Can Increasing the Manufacturer's Recommended Shortest Curing Time of High-intensity Light-emitting Diodes Adequately Cure Sealants?

    Science.gov (United States)

    Branchal, Caroline F; Wells, Martha H; Tantbirojn, Daranee; Versluis, Antheunis

    2015-01-01

    To investigate sealant depth of cure after increasing the curing times of high-intensity light-emitting diode units (LEDs). Three sealants (opaque-unfilled, opaque-filled, and clear-filled) were light cured in a covered-slot mold with: (a) three LEDs (VALO, SmartLite, Fusion) for six to 15 seconds; and (b) a quartz-tungsten halogen (QTH) light for 40 seconds as a control (N=10). Twenty-four hours after light curing, microhardness was measured at the sealant surface and through the depth at 0.5 mm increments. Results were analyzed via analysis of variance followed by the Student-Newman-Keuls test (significance level 0.05). The opaque-filled and clear-filled sealants cured with VALO for six or nine seconds had hardness values that were statistically equivalent to or better than the QTH to a depth of 1.5 mm. Using Fusion for 10 seconds (exposure limit) did not adequately cure the three sealants beyond one mm. SmartLite at 15 seconds (maximum exposure period without overheating) did not adequately cure the sealants beyond 0.5 mm. Among the tested high-intensity LEDs, only VALO at double or triple the manufacturers' shortest curing time (six or nine seconds) provided adequate curing of opaque-filled and clear-filled sealants at 1.5 mm depth compared to the 40-second QTH light.

  12. Stable White Light Electroluminescence from Highly Flexible Polymer/ZnO Nanorods Hybrid Heterojunction Grown at 50 degrees C.

    Science.gov (United States)

    Zainelabdin, A; Zaman, S; Amin, G; Nur, O; Willander, M

    2010-06-04

    Stable intrinsic white light-emitting diodes were fabricated from c-axially oriented ZnO nanorods (NRs) grown at 50 degrees C via the chemical bath deposition on top of a multi-layered poly(9,9-dioctylfluorene-co-N-(4-butylpheneylamine)diphenylamine)/poly(9,9dioctyl-fluorene) deposited on PEDOT:PSS on highly flexible plastic substrate. The low growth temperature enables the use of a variety of flexible plastic substrates. The fabricated flexible white light-emitting diode (FWLED) demonstrated good electrical properties and a single broad white emission peak extending from 420 nm and up to 800 nm combining the blue light emission of the polyflourene (PFO) polymer layer with the deep level emission (DLEs) of ZnO NRs. The influence of the temperature variations on the FWLED white emissions characteristics was studied and the devices exhibited high operation stability. Our results are promising for the development of white lighting sources using existing lighting glass bulbs, tubes, and armature technologies.

  13. Uncoupling High Light Responses from Singlet Oxygen Retrograde Signaling and Spatial-Temporal Systemic Acquired Acclimation.

    Science.gov (United States)

    Carmody, Melanie; Crisp, Peter A; d'Alessandro, Stefano; Ganguly, Diep; Gordon, Matthew; Havaux, Michel; Albrecht-Borth, Verónica; Pogson, Barry J

    2016-07-01

    Distinct ROS signaling pathways initiated by singlet oxygen ((1)O2) or superoxide and hydrogen peroxide have been attributed to either cell death or acclimation, respectively. Recent studies have revealed that more complex antagonistic and synergistic relationships exist within and between these pathways. As specific chloroplastic ROS signals are difficult to study, rapid systemic signaling experiments using localized high light (HL) stress or ROS treatments were used in this study to uncouple signals required for direct HL and ROS perception and distal systemic acquired acclimation (SAA). A qPCR approach was chosen to determine local perception and distal signal reception. Analysis of a thylakoidal ascorbate peroxidase mutant (tapx), the (1)O2-retrograde signaling double mutant (ex1/ex2), and an apoplastic signaling double mutant (rbohD/F) revealed that tAPX and EXECUTER 1 are required for both HL and systemic acclimation stress perception. Apoplastic membrane-localized RBOHs were required for systemic spread of the signal but not for local signal induction in directly stressed tissues. Endogenous ROS treatments revealed a very strong systemic response induced by a localized 1 h induction of (1)O2 using the conditional flu mutant. A qPCR time course of (1)O2 induced systemic marker genes in directly and indirectly connected leaves revealed a direct vascular connection component of both immediate and longer term SAA signaling responses. These results reveal the importance of an EXECUTER-dependent (1)O2 retrograde signal for both local and long distance RBOH-dependent acclimation signaling that is distinct from other HL signaling pathways, and that direct vascular connections have a role in spatial-temporal SAA induction. © 2016 American Society of Plant Biologists. All Rights Reserved.

  14. High modulation bandwidth of a light-emitting diode with surface plasmon coupling (Conference Presentation)

    Science.gov (United States)

    Lin, Chun-Han; Tu, Charng-Gan; Yao, Yu-Feng; Chen, Sheng-Hung; Su, Chia-Ying; Chen, Hao-Tsung; Kiang, Yean-Woei; Yang, Chih-Chung

    2017-02-01

    Besides lighting, LEDs can be used for indoor data transmission. Therefore, a large modulation bandwidth becomes an important target in the development of visible LED. In this regard, enhancing the radiative recombination rate of carriers in the quantum wells of an LED is a useful method since the modulation bandwidth of an LED is related to the carrier decay rate besides the device RC time constant To increase the carrier decay rate in an LED without sacrificing its output power, the technique of surface plasmon (SP) coupling in an LED is useful. In this paper, the increases of modulation bandwidth by reducing mesa size, decreasing active layer thickness, and inducing SP coupling in blue- and green-emitting LEDs are illustrated. The results are demonstrated by comparing three different LED surface structures, including bare p-type surface, GaZnO current spreading layer, and Ag nanoparticles (NPs) for inducing SP coupling. In a single-quantum-well, blue-emitting LED with a circular mesa of 10 microns in radius, SP coupling results in a modulation bandwidth of 528.8 MHz, which is believed to be the record-high level. A smaller RC time constant can lead to a higher modulation bandwidth. However, when the RC time constant is smaller than 0.2 ns, its effect on modulation bandwidth saturates. The dependencies of modulation bandwidth on injected current density and carrier decay time confirm that the modulation bandwidth is essentially inversely proportional to a time constant, which is inversely proportional to the square-root of carrier decay rate and injected current density.

  15. A simple preparation of nitrogen doped titanium dioxide nanocrystals with exposed (001) facets with high visible light activity.

    Science.gov (United States)

    Zhou, Xiaosong; Peng, Feng; Wang, Hongjuan; Yu, Hao; Fang, Yueping

    2012-01-14

    Nanoscaled nitrogen doped anatase TiO(2) with dominant (001) facets, which exhibited high photocatalytic activity and excellent photoelectrochemical properties under visible light irradiation, was successfully synthesized by solvothermal treatment of TiN in acidic NaBF(4) solution for the first time. This journal is © The Royal Society of Chemistry 2012

  16. Rapid Analysis of Apolar Low Molecular Weight Constituents in Wood Using High Pressure Liquid Chromatography with Evaporative Light Scattering Detection

    NARCIS (Netherlands)

    Claassen, F.W.; Haar, van de C.; Beek, van T.A.; Dorado, J.; Martinez-Inigo, M.; Sierra-Alvarez, R.

    2000-01-01

    A new high pressure liquid chromatographic method with evaporative light scattering detection was developed for the qualitative and quantitative analysis of apolar, low molecular weight constituents in wood. The wood extractives were obtained by means of a 6 h Soxhlet extraction with acetone. The

  17. Time-Valued-Technology: A Light-Emitting Diode Case Study for Determining Replacement Strategy for High Technology Infrastructure Items

    Science.gov (United States)

    2012-03-22

    viii I. Introduction .....................................................................................................................1...DIODE CASE STUDY FOR DETERMINING REPLACEMENT STRATEGY FOR HIGH TECHNOLOGY INFRASTRUCTURE ITEMS I. Introduction In an effort to support cost... MCDM Models, Algorithms, Theory, and Applications. Kluwer Academic Publishers. Norwell, Ma. GE Commercial Lighting Products. Retrieved 11/2/2011

  18. Inactivation of Staphylococcus saprophyticus in chicken meat and exudate using high pressure processing, gamma radiation, and ultraviolet light

    Science.gov (United States)

    Stapylococcus saprophyticus is a common contaminant in foods and causes urinary tract infections in humans. Three nonthermal food safety intervention technologies used to improve the safety foods include high pressure processing (HPP), ionizing (gamma) radiation (GR), and ultraviolet light (UV-C). A...

  19. Growth under UV-B radiation increases tolerance to high-light stress in pea and bean plants

    NARCIS (Netherlands)

    Bolink, EM; van Schalkwijk, [No Value; Posthumus, F; van Hasselt, PR

    Pea (Pisum sativum L.) and bean (Phaseolus vulgaris L.) plants were exposed to enhanced levels of UV-B radiation in a growth chamber. Leaf discs of UV-B treated and control plants were exposed to high-light (HL) stress (PAR: 1200 mu mol m(-2) s(-1)) to study whether pre-treatment with UV-B affected

  20. Comparison of Bond Strength of Metal and Ceramic Brackets Bonded with Conventional and High-Power LED Light Curing Units

    Directory of Open Access Journals (Sweden)

    Javad Chalipa

    2017-01-01

    Full Text Available Objectives: The aim of this study was to evaluate the effect of conventional and high-power light emitting diode (LED light curing units on shear bond strength (SBS of metal and ceramic brackets to tooth surface.Materials and Methods: Forty sound bovine maxillary central incisors were used for the study. The teeth were divided into four groups (n=10. Teeth surfaces were etched with 37% phosphoric acid for 20 seconds. After applying a uniform layer of adhesive primer on the etched enamel, composite was placed on the base of brackets. The samples were light cured according to the manufacturer’s instructions and thermocycled. The SBS was measured. The failure mode was scored using the adhesive remnant index (ARI.Results: The mean SBS of samples in groups A (high-power LED, metal bracket, B (high-power LED, ceramic bracket, C (conventional LED, metal bracket and D (conventional LED, ceramic bracket was 23.1±3.69, 10.7±2.06, 24.92±6.37 and 10.74±3.18MPa, respectively. The interaction effect of type of LED unit (high-power/conventional and bracket type on SBS was not statistically significant (P=0.483. In general, type of LED unit did not affect SBS. Type of bracket significantly affected SBS (P<0.001. The ARI score was not significantly influenced by the interaction between the type of LED unit and bracket. Conclusions: The obtained SBS is the same for both bracket types by use of high-power and conventional LED light curing units. Regardless of the type of LED unit, SBS of ceramic brackets was significantly lower than that of metal brackets.Keywords: Orthodontic Brackets; Shear Strength; Light-Curing of Dental Adhesives

  1. Comparison of Bond Strength of Metal and Ceramic Brackets Bonded with Conventional and High-Power LED Light Curing Units

    OpenAIRE

    Chalipa, Javad; Jalali, Yasamin Farajzadeh; Gorjizadeh, Fatemeh; Baghaeian, Pedram; Hoseini, Mohammad Hashem; Mortezai, Omid

    2016-01-01

    Objectives: The aim of this study was to evaluate the effect of conventional and high-power light emitting diode (LED) light curing units on shear bond strength (SBS) of metal and ceramic brackets to tooth surface.Materials and Methods: Forty sound bovine maxillary central incisors were used for the study. The teeth were divided into four groups (n=10). Teeth surfaces were etched with 37% phosphoric acid for 20 seconds. After applying a uniform layer of adhesive primer on the etched enamel, c...

  2. Plasticity in the proteome of Emiliania huxleyi CCMP 1516 to extremes of light is highly targeted.

    Science.gov (United States)

    McKew, Boyd A; Lefebvre, Stephane C; Achterberg, Eric P; Metodieva, Gergana; Raines, Christine A; Metodiev, Metodi V; Geider, Richard J

    2013-10-01

    Optimality principles are often applied in theoretical studies of microalgal ecophysiology to predict changes in allocation of resources to different metabolic pathways, and optimal acclimation is likely to involve changes in the proteome, which typically accounts for > 50% of cellular nitrogen (N). We tested the hypothesis that acclimation of the microalga Emiliania huxleyi CCMP 1516 to suboptimal vs supraoptimal light involves large changes in the proteome as cells rebalance the capacities to absorb light, fix CO2 , perform biosynthesis and resist photooxidative stress. Emiliania huxleyi was grown in nutrient-replete continuous culture at 30 (LL) and 1000 μmol photons m(-2) s(-1) (HL), and changes in the proteome were assessed by LC-MS/MS shotgun proteomics. Changes were most evident in proteins involved in the light reactions of photosynthesis; the relative abundance of photosystem I (PSI) and PSII proteins was 70% greater in LL, light-harvesting fucoxanthin-chlorophyll proteins (Lhcfs) were up to 500% greater in LL and photoprotective LI818 proteins were 300% greater in HL. The marked changes in the abundances of Lhcfs and LI818s, together with the limited plasticity in the bulk of the E. huxleyi proteome, probably reflect evolutionary pressures to provide energy to maintain metabolic capabilities in stochastic light environments encountered by this species in nature. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

  3. Fast forward genetics to identify mutations causing a high light tolerant phenotype in Chlamydomonas reinhardtii by whole-genome-sequencing.

    Science.gov (United States)

    Schierenbeck, Lisa; Ries, David; Rogge, Kristin; Grewe, Sabrina; Weisshaar, Bernd; Kruse, Olaf

    2015-02-06

    High light tolerance of microalgae is a desired phenotype for efficient cultivation in large scale production systems under fluctuating outdoor conditions. Outdoor cultivation requires the use of either wild-type or non-GMO derived mutant strains due to safety concerns. The identification and molecular characterization of such mutants derived from untagged forward genetics approaches was limited previously by the tedious and time-consuming methods involving techniques such as classical meiotic mapping. The combination of mapping with next generation sequencing technologies offers alternative strategies to identify genes involved in high light adaptation in untagged mutants. We used the model alga Chlamydomonas reinhardtii in a non-GMO mutation strategy without any preceding crossing step or pooled progeny to identify genes involved in the regulatory processes of high light adaptation. To generate high light tolerant mutants, wildtype cells were mutagenized only to a low extent, followed by a stringent selection. We performed whole-genome sequencing of two independent mutants hit1 and hit2 and the parental wildtype. The availability of a reference genome sequence and the removal of shared bakground variants between the wildtype strain and each mutant, enabled us to identify two single nucleotide polymorphisms within the same gene Cre02.g085050, hereafter called LRS1 (putative Light Response Signaling protein 1). These two independent single amino acid exchanges are both located in the putative WD40 propeller domain of the corresponding protein LRS1. Both mutants exhibited an increased rate of non-photochemical-quenching (NPQ) and an improved resistance against chemically induced reactive oxygen species. In silico analyses revealed homology of LRS1 to the photoregulatory protein COP1 in plants. In this work we identified the nuclear encoded gene LRS1 as an essential factor for high light adaptation in C. reinhardtii. The causative random mutation within this gene was

  4. 49 CFR 542.1 - Procedures for selecting new light duty truck lines that are likely to have high or low theft rates.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 6 2010-10-01 2010-10-01 false Procedures for selecting new light duty truck... OF TRANSPORTATION PROCEDURES FOR SELECTING LIGHT DUTY TRUCK LINES TO BE COVERED BY THE THEFT PREVENTION STANDARD § 542.1 Procedures for selecting new light duty truck lines that are likely to have high...

  5. Adaptation of photosystem II to high and low light in wild-type and triazine-resistant Canola plants: analysis by a fluorescence induction algorithm

    NARCIS (Netherlands)

    Rensen, van J.J.S.; Vredenberg, W.J.

    2011-01-01

    Plants of wild-type and triazine-resistant Canola (Brassica napus L.) were exposed to very high light intensities and after 1 day placed on a laboratory table at low light to recover, to study the kinetics of variable fluorescence after light, and after dark-adaptation. This cycle was repeated

  6. 1.9 W yellow, CW, high-brightness light from a high efficiency semiconductor laser-based system

    DEFF Research Database (Denmark)

    Hansen, Anders Kragh; Christensen, Mathias; Noordegraaf, Danny

    2017-01-01

    , imaging, flow cytometry, and cancer treatment. However, direct generation of yellow light from semiconductors with sufficient beam quality and power has so far eluded researchers. Meanwhile, tapered semiconductor lasers at near-infrared wavelengths have recently become able to provide neardiffraction...

  7. Concentration of phenolic compounds is increased in lettuce grown under high light intensity and elevated CO2.

    Science.gov (United States)

    Pérez-López, Usue; Sgherri, Cristina; Miranda-Apodaca, Jon; Micaelli, Francesco; Lacuesta, Maite; Mena-Petite, Amaia; Quartacci, Mike Frank; Muñoz-Rueda, Alberto

    2018-02-01

    The present study was focused on lettuce, a widely consumed leafy vegetable for the large number of healthy phenolic compounds. Two differently-pigmented lettuce cultivars, i.e. an acyanic-green leaf cv. and an anthocyanic-red one, were grown under high light intensity or elevated CO2 or both in order to evaluate how environmental conditions may affect the production of secondary phenolic metabolites and, thus, lettuce quality. Mild light stress imposed for a short time under ambient or elevated CO2 concentration increased phenolics compounds as well as antioxidant capacity in both lettuce cvs, indicating how the cultivation practice could enhance the health-promoting benefits of lettuce. The phenolic profile depended on pigmentation and the anthocyanic-red cv. always maintained a higher phenolic amount as well as antioxidant capacity than the acyanic-green one. In particular, quercetin, quercetin-3-O-glucuronide, kaempferol, quercitrin and rutin accumulated under high light or high CO2 in the anthocyanic-red cv., whereas cyanidin derivatives were responsive to mild light stress, both at ambient and elevated CO2. In both cvs total free and conjugated phenolic acids maintained higher values under all altered environmental conditions, whereas luteolin reached significant amounts when both stresses were administered together, indicating, in this last case, that the enzymatic regulation of the flavonoid synthesis could be differently affected, the synthesis of flavones being favored. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  8. Development of high-fidelity multiphysics system for light water reactor analysis

    Science.gov (United States)

    Magedanz, Jeffrey W.

    There has been a tendency in recent years toward greater heterogeneity in reactor cores, due to the use of mixed-oxide (MOX) fuel, burnable absorbers, and longer cycles with consequently higher fuel burnup. The resulting asymmetry of the neutron flux and energy spectrum between regions with different compositions causes a need to account for the directional dependence of the neutron flux, instead of the traditional diffusion approximation. Furthermore, the presence of both MOX and high-burnup fuel in the core increases the complexity of the heat conduction. The heat transfer properties of the fuel pellet change with irradiation, and the thermal and mechanical expansion of the pellet and cladding strongly affect the size of the gap between them, and its consequent thermal resistance. These operational tendencies require higher fidelity multi-physics modeling capabilities, and this need is addressed by the developments performed within this PhD research. The dissertation describes the development of a High-Fidelity Multi-Physics System for Light Water Reactor Analysis. It consists of three coupled codes -- CTF for Thermal Hydraulics, TORT-TD for Neutron Kinetics, and FRAPTRAN for Fuel Performance. It is meant to address these modeling challenges in three ways: (1) by resolving the state of the system at the level of each fuel pin, rather than homogenizing entire fuel assemblies, (2) by using the multi-group Discrete Ordinates method to account for the directional dependence of the neutron flux, and (3) by using a fuel-performance code, rather than a Thermal Hydraulics code's simplified fuel model, to account for the material behavior of the fuel and its feedback to the hydraulic and neutronic behavior of the system. While the first two are improvements, the third, the use of a fuel-performance code for feedback, constitutes an innovation in this PhD project. Also important to this work is the manner in which such coupling is written. While coupling involves combining

  9. High efficiency organic light-emitting display using selective spectral photo-recycling

    Science.gov (United States)

    Lee, Eunjung; Song, Jang-Kun

    2012-11-01

    Here, we introduce a selective photo-recycling scheme for organic light-emitting diode (OLED) displays. The conventional photo-recycling method, which uses a recycling film named DBEF, diminishes the ambient contrast ratio of the OLED display, so it is not suitable for display applications. The selective recycling scheme, which uses a cholesteric liquid crystal (CLC) layer that recycles light only in a specific spectral range, can minimize the deterioration of the ambient contrast ratio while improving the photo-efficiency. We found that the aperture ratio of the OLED display influences the recycling efficiency significantly, and that a thin CLC layer diminishes the ambient contrast ratio less than a thick CLC layer while it still recycles the emitted light. By recycling the blue spectral range, one can improve the lifetime of blue OLE material, which has the shortest lifetime, or reduce the size of the blue pixel, which has the largest size among red, green, and blue pixels.

  10. Cesium hafnium chloride: A high light yield, non-hygroscopic cubic crystal scintillator for gamma spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Burger, Arnold, E-mail: aburger@fisk.edu [Department of Life and Physical Sciences, Fisk University, Nashville, Tennessee 37208 (United States); Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee 37235 (United States); Rowe, Emmanuel; Groza, Michael; Morales Figueroa, Kristle [Department of Life and Physical Sciences, Fisk University, Nashville, Tennessee 37208 (United States); Cherepy, Nerine J.; Beck, Patrick R.; Hunter, Steven; Payne, Stephen A. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

    2015-10-05

    We report on the scintillation properties of Cs{sub 2}HfCl{sub 6} (cesium hafnium chloride or CHC) as an example of a little-known class of non-hygroscopic compounds having the generic cubic crystal structure of K{sub 2}PtCl{sub 6}. The crystals are easily growable from the melt using the Bridgman method with minimal precursor treatments or purification. CHC scintillation is centered at 400 nm, with a principal decay time of 4.37 μs and a light yield of up to 54 000 photons/MeV when measured using a silicon CCD photodetector. The light yield is the highest ever reported for an undoped crystal, and CHC also exhibits excellent light yield nonproportionality. These desirable properties allowed us to build and test CHC gamma-ray spectrometers providing energy resolution of 3.3% at 662 keV.

  11. Silicon-Light: a European FP7 Project Aiming at High Efficiency Thin Film Silicon Solar Cells on Foil

    DEFF Research Database (Denmark)

    Soppe, W.; Haug, F.-J.; Couty, P.

    2011-01-01

    calculations of ideal nanotextures for light trapping in thin film silicon solar cells; the fabrication of masters and the replication and roll-to-roll fabrication of these nanotextures. Further, results on ITO variants with improved work function are presented. Finally, the status of cell fabrication on foils......Silicon-Light is a European FP7 project, which started January 1st, 2010 and aims at development of low cost, high-efficiency thin film silicon solar cells on foil. Three main routes are explored to achieve these goals: a) advanced light trapping by implementing nanotexturization through UV Nano...... with nanotexture is shown. Microcrystalline and amorphous silicon single junction cells with stable efficiencies with more than 8 % have been made, paving the way towards a-Si/ c-Si tandem cells with more than 11% efficiency....

  12. Genetic Algorithm for Innovative Device Designs in High-Efficiency III–V Nitride Light-Emitting Diodes

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Di [Rensselaer Polytechnic Inst., Troy, NY (United States). Dept. of Electrical, Computer and Systems Engineering; Schubert, Martin F. [Rensselaer Polytechnic Inst., Troy, NY (United States). Dept. of Electrical, Computer and Systems Engineering; Cho, Jaehee [Rensselaer Polytechnic Inst., Troy, NY (United States). Dept. of Electrical, Computer and Systems Engineering; Schubert, E. Fred [Rensselaer Polytechnic Inst., Troy, NY (United States). Dept. of Electrical, Computer and Systems Engineering; Crawford, Mary H. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Koleske, Daniel D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Shim, Hyunwook [Samsung LED, R& D Inst., Suwon (Republic of Korea); Sone, Cheolsoo [Samsung LED, R& D Inst., Suwon (Republic of Korea)

    2012-01-01

    Light-emitting diodes are becoming the next-generation light source because of their prominent benefits in energy efficiency, versatility, and benign environmental impact. However, because of the unique polarization effects in III–V nitrides and the high complexity of light-emitting diodes, further breakthroughs towards truly optimized devices are required. Here we introduce the concept of artificial evolution into the device optimization process. Reproduction and selection are accomplished by means of an advanced genetic algorithm and device simulator, respectively. We demonstrate that this approach can lead to new device structures that go beyond conventional approaches. The innovative designs originating from the genetic algorithm and the demonstration of the predicted results by implementing structures suggested by the algorithm establish a new avenue for complex semiconductor device design and optimization.

  13. A high-light-harvesting-efficiency coumarin dye for stable dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Z.S.; Cui, Y.; Hara, K. [National Institute of Advanced Industrial, Science and Technology (AIST), Tsukuba, Ibaraki (Japan); Dan-oh, Y.; Kasada, C.; Shinpo, A. [Hayashibara Biochemical Laboratories, Inc., Okayama (Japan)

    2007-04-20

    A new coumarin dye for use in dye-sensitized solar cells (DSSCs) is reported. It exhibits near-unity light harvesting efficiency and incident photon-to-electron conversion efficiency over a wide spectral region in 6 {mu}m transparent TiO{sub 2} films. DSSCs based on this metal-free organic dye show long-term stability and power-conversion efficiencies of around 6 % under continuous light-soaking stress for up to 1000 h. (Abstract Copyright [2007], Wiley Periodicals, Inc.)

  14. CO2 laser-fabricated cladding light strippers for high-power fiber lasers and amplifiers.

    Science.gov (United States)

    Boyd, Keiron; Simakov, Nikita; Hemming, Alexander; Daniel, Jae; Swain, Robert; Mies, Eric; Rees, Simon; Andrew Clarkson, W; Haub, John

    2016-04-10

    We present and characterize a simple CO2 laser processing technique for the fabrication of compact all-glass optical fiber cladding light strippers. We investigate the cladding light loss as a function of radiation angle of incidence and demonstrate devices in a 400 μm diameter fiber with cladding losses of greater than 20 dB for a 7 cm device length. The core losses are also measured giving a loss of laser diode with minimal heating of the fiber coating and packaging adhesives.

  15. Light intensity and SNR improvement for high-resolution optical imaging via time multiplexed pinhole arrays.

    Science.gov (United States)

    Schwarz, Ariel; Shemer, Amir; Zalevsky, Zeev

    2014-07-10

    In this paper, we present a novel method for pinhole optics with variable pinhole arrays. The imaging system is based on a time multiplexing method using variable and moving pinhole arrays. The improved resolution and signal-to-noise ratio are achieved with improved light intensity in the same exposure time, compared with that of a one-pinhole system. This new configuration preserves the advantages of pinhole optics while solving the resolution limitation problem and the long exposure time of such systems. The system also can be used as an addition to several existing optical systems, which use visible and invisible light and x-ray systems.

  16. High-Efficiency Nitride-Based Light-Emitting Diodes with Moth-Eye Structure

    Science.gov (United States)

    Kasugai, Hideki; Miyake, Yasuto; Honshio, Akira; Mishima, Shunsuke; Kawashima, Takeshi; Iida, Kazuyoshi; Iwaya, Motoaki; Kamiyama, Satoshi; Amano, Hiroshi; Akasaki, Isamu; Kinoshita, Hiroyuki; Shiomi, Hiromu

    2005-10-01

    Nitride-based blue light-emitting diodes (LEDs) with a moth-eye structure on the back of a 6H-SiC substrate have been developed. The moth-eye LED has a roughness less than the optical wavelength at the back surface of the SiC substrate fabricated by reactive ion etching (RIE) with CF4 gas. The light extraction efficiency and corresponding output power have been increased to 3.8 times those of a LED with a conventional structure. The experimental findings agree with the results of a theoretical analysis of the effect of the moth-eye structure.

  17. Ultra-high enhancement of light focusing through disordered media controlled by mega-pixel modes (Conference Presentation)

    Science.gov (United States)

    Yu, Hyeonseung; Lee, KyeoReh; Park, YongKeun

    2017-02-01

    Developing an efficient strategy for light focusing through scattering media is an important topic in the study of multiple light scattering. The enhancement factor of the light focusing, defined as the ratio between the optimized intensity and the background intensity is proportional to the number of controlling modes in a spatial light modulator (SLM). The demonstrated enhancement factors in previous studies are typically less than 1,000 due to several limiting factors, such as the slow refresh rate of a LCoS SLM, long optimization time, and lack of an efficient algorithm for high controlling modes. A digital micro-mirror device is an amplitude modulator, which is recently widely used for fast optimization through dynamic biological tissues. The fast frame rate of the DMD up to 16 kHz can also be exploited for increasing the number of controlling modes. However, the manipulation of large pattern data and efficient calculation of the optimized pattern remained as an issue. In this work, we demonstrate the enhancement factor more than 100,000 in focusing through scattering media by using 1 Mega controlling modes of a DMD. Through careful synchronization between a DMD, a photo-detector and an additional computer for parallel optimization, we achieved the unprecedented enhancement factor with 75 mins of the optimization time. We discuss the design principles of the system and the possible applications of the enhanced light focusing.

  18. Quasi-phase matching of soft X-ray light from high-order harmonic generation using waveguide structures

    Science.gov (United States)

    Gibson, Emily Abbott

    Ultrafast laser technology has made it possible to achieve extremely high field intensities, above 1018 W/cm2, or alternatively, light pulses with extremely short time durations corresponding to only a few femtoseconds (10-15 s). In this high intensity regime, the laser field energy is comparable to the binding energy of an electron to an atom. One result of this highly non-perturbative atom-light interaction is the process of high-order harmonic generation (HHG). In HHG, the strong laser field first ionizes the atom. The subsequent motion of the free electron is controlled by the oscillating laser field, and the electron can reach kinetic energies many times that of the original binding energy to the atom. The high energy electron can then recollide with its parent ion, releasing a high energy photon. This process occurs for many atoms driven coherently by the same laser field, resulting in a coherent, laser-like beam of ultrafast light spanning the ultraviolet to soft X-ray regions of the spectrum. In this thesis, I will present two major breakthroughs in the field of high harmonic generation. First, I will discuss work on quasi-phase matching of high harmonic generation, which has allowed increased conversion efficiency of high harmonic light up to the water window region of the soft X-ray spectrum (˜300 eV) for the first time.[31] This spectral region is significant because at these photon energies, water is transparent while carbon strongly absorbs, making it a useful light source for very high resolution contrast microscopy on biological samples. Since the resolution is on order of the wavelength of the light (˜4 nm for 300 eV), detailed structures of cells and DNA can be viewed. A table-top source of light in the water window soft X-ray region would greatly benefit biological and medical research. Second, I will present work on the generation of very high harmonic orders from ions. This work is the first to show that harmonic emission from ions is of

  19. All-photonic drying and sintering process via flash white light combined with deep-UV and near-infrared irradiation for highly conductive copper nano-ink

    OpenAIRE

    Hwang, Hyun-Jun; Oh, Kyung-Hwan; Kim, Hak-Sung

    2016-01-01

    We developed an ultra-high speed photonic sintering method involving flash white light (FWL) combined with near infrared (NIR) and deep UV light irradiation to produce highly conductive copper nano-ink film. Flash white light irradiation energy and the power of NIR/deep UV were optimized to obtain high conductivity Cu films. Several microscopic and spectroscopic characterization techniques such as scanning electron microscopy (SEM), a x-ray diffraction (XRD), and Fourier-transform infrared (F...

  20. New concept for organic light-emitting devices under high excitations using emission from a metal-free area

    Science.gov (United States)

    Slowik, Irma; Fischer, Axel; Gutsche, Stefan; Brückner, Robert; Fröb, Hartmut; Lenk, Simone; Reineke, Sebastian; Leo, Karl

    2016-04-01

    In this work, a new organic light-emitting device (OLED) structure is proposed that allows light-emission from a metal-free device region, thus reducing the hurdles towards an electrically pumped organic solid state laser (OSL). Our design concept employs a stepwise change from a highly conductive but opaque metal part to a highly transparent but less conductive intrinsic emission layer. Here, the high current densities are localized to an area of a few micrometer in square, which is in the range of the mode volume of the transverse mode of an organic vertical-cavity surface-emitting laser (VCSEL). Besides these experimental results, we present findings from simulations which further support the feasibility of our design concept. Using an equivalent circuit approach, representing the current flow in the device, we calculate the time-dependent length of the emission zone and give estimations for appropriate material parameters.

  1. Very high coupling of TM polarised light in photonic crystal directional couplers

    DEFF Research Database (Denmark)

    Borel, Peter Ingo; Thorhauge, Morten; Frandsen, Lars Hagedorn

    2003-01-01

    The experimental and simulated spectra for TE and TM polarised light for the transmission through photonic crystal directional couplers are presented. The 3D FDTD simulations successfully explain all the major features of the experimental spectra as well as the actual transmission level. Especially...

  2. Highly Efficient p-i-n Type Organic Light-emitting Diodes Using ...

    African Journals Online (AJOL)

    stack of thin organic layers sandwiched between a transparent anode and a metallic cathode. The anode injects holes into the first organic layer referred as the “hole injection layer ... indium tin oxide (ITO) is used as an anode, while the cathode is a low ... the calibrated silicon photodiode above the OLEDs to detect the light ...

  3. Combining light-harvesting with detachability in high-efficiency thin-film silicon solar cells.

    Science.gov (United States)

    Ram, Sanjay K; Desta, Derese; Rizzoli, Rita; Bellettato, Michele; Lyckegaard, Folmer; Jensen, Pia B; Jeppesen, Bjarke R; Chevallier, Jacques; Summonte, Caterina; Larsen, Arne Nylandsted; Balling, Peter

    2017-06-01

    Efforts to realize thin-film solar cells on unconventional substrates face several obstacles in achieving good energy-conversion efficiency and integrating light-management into the solar cell design. In this report a technique to circumvent these obstacles is presented: transferability and an efficient light-harvesting scheme are combined for thin-film silicon solar cells by the incorporation of a NaCl layer. Amorphous silicon solar cells in p-i-n configuration are fabricated on reusable glass substrates coated with an interlayer of NaCl. Subsequently, the solar cells are detached from the substrate by dissolution of the sacrificial NaCl layer in water and then transferred onto a plastic sheet, with a resultant post-transfer efficiency of 9%. The light-trapping effect of the surface nanotextures originating from the NaCl layer on the overlying solar cell is studied theoretically and experimentally. The enhanced light absorption in the solar cells on NaCl-coated substrates leads to significant improvement in the photocurrent and energy-conversion efficiency in solar cells with both 350 and 100 nm thick absorber layers, compared to flat-substrate solar cells. Efficient transferable thin-film solar cells hold a vast potential for widespread deployment of off-grid photovoltaics and cost reduction.

  4. Current Spreading Layer with High Transparency and Conductivity for near-ultraviolet light emitting diodes

    DEFF Research Database (Denmark)

    Lin, Li; Jensen, Flemming; Herstrøm, Berit

    Transparent conductive aluminum-doped zinc oxide (AZO) layer was deposited on GaN-based near-ultraviolet (NUV) light emitting epitaxial wafers as current spreading layer by a sputtering process. Efforts were made to improve the electrical properties of AZO in order to produce ohmic contact....

  5. High efficiency GaN-based LEDs: light extraction by photonic crystals

    Science.gov (United States)

    David, A.

    2006-11-01

    Gallium nitride (GaN)-based light-emitting diodes (LEDs) are seen as promising candidates for the replacement of conventional light sources by all-solid state lighting. However, their efficiency is currently limited by the difficulty of extracting the light emitted within the LED, which is mostly trapped in the material by total internal reflection. This book explores the use of photonic crystals (PhCs) to increase light extraction in a deterministic fashion. PhCs act as bi-dimensional diffraction gratings which extract guided light from the LED. However, the peculiarities of GaN epitaxial layers make the optimization of such structures challenging. In particular, it turns out that the vertical structure of the LED has to be engineered so that all of the guided light may interact efficiently with the photonic crystal. Various implementations of such LEDs are proposed, modeled (by 3D methods), fabricated and characterized. Diodes GaN à haute efficacité: extraction de la lumière par cristaux photoniques. Les diodes électro-luminescentes à base de nitrure de gallium (GaN) ont le potentiel de remplacer les sources d'éclairage conventionnel en offrant des économies d'énergie considérables. Toutefois, leur efficacité est actuellement limitée par le problème de l'extraction de la lumière émise dans la diode, dont une grande partie reste piégée dans le matériau par réflexion totale interne. Cet ouvrage explore l'emploi de cristaux photoniques (PhC) pour augmenter l'extraction de la lumière de façon déterministe. Les PhC sont ici employés comme réseau de diffraction à deux dimensions afin d'extraire la lumière guidée hors de la diode. Les caractéristiques des couches épitaxiées de GaN rendent toutefois l'optimisation de telles structures difficile. Notamment, il apparaît que la structure verticale de la diode doit être adaptée pour que toute la lumière guidée puisse interagir efficacement avec les cristaux photoniques. Diverses impl

  6. Investigation of very high burnup UO{sub 2} fuels in Light Water Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Cappia, Fabiola

    2017-03-27

    Historically, the average discharge burnup of Light Water Reactor (LWR) fuel has increased almost continuously. On one side, increase in the average discharge burnup is attractive because it contributes to decrease part of the fuel cycle costs. On the other side, it raises the practical problem of predicting the performance, longevity and properties of reactor fuel elements upon accumulation of irradiation damage and fission products both during in-reactor operation and after discharge. Performance of the fuel and structural components of the core is one of the critical areas on which the economic viability and public acceptance of nuclear energy production hinges. Along the pellet radius, the fuel matrix is subjected to extremely heterogeneous alteration and damage, as a result of temperature and burnup gradients. In particular, in the peripheral region of LWR UO{sub 2} fuel pellets, when the local burnup exceeds 50-70 GWd/tHM, a microstructural transformation starts to take place, as a consequence of enhanced accumulation of radiation damage, fission products and limited thermal recovery. The newly formed structure is commonly named High Burnup Structure (HBS). The HBS is characterised by three main features: (a) formation of submicrometric grains from the original grains, (b) depletion of fission gas from the fuel matrix, (c) steep increase in the porosity, which retains most of the gas depleted from the fuel matrix. The last two aspects rose significant attention because of the important impact of the fission gas behaviour on integral fuel performance. The porosity increase controls the gas-driven swelling, worsening the cladding loading once the fuel-cladding gap is closed. Another concern is that the large retention of fission gas within the HBS could lead to significant release at high burnups through the degradation of thermal conductivity or contribute to fuel pulverisation during accidental conditions. Need of more experimental investigations about the

  7. High coupling efficiency of foam spherical hohlraum driven by 2ω laser light

    Science.gov (United States)

    Chen, Yao-Hua; Lan, Ke; Zheng, Wanguo; Campbell, E. M.

    2018-02-01

    The majority of solid state laser facilities built for laser fusion research irradiate targets with third harmonic light (0.35 μm) up-converted from the fundamental Nd wavelength at 1.05 μm. The motivation for this choice of wavelength is improved laser-plasma coupling. Significant disadvantages to this choice of wavelength are the reduced damage threshold of optical components and the efficiency of energy conversion to third harmonic light. Both these issues are significantly improved if second harmonic (0.53 μm) radiation is used, but theory and experiments have shown lower optical to x-ray energy conversion efficiency and increased levels of laser-plasma instabilities, resulting in reduced laser-target coupling. In this letter, we propose to use a 0.53 μm laser for the laser ignition facilities and use a low density foam wall to increase the coupling efficiency from the laser to the capsule and present two-dimensional radiation-hydrodynamic simulations of 0.53 μm laser light irradiating an octahedral-spherical hohlraum with a low density foam wall. The simulations show that the reduced optical depth of the foam wall leads to an increased laser-light conversion into thermal x-rays and about 10% higher radiation flux on the capsule than that achieved with 0.35 μm light irradiating a solid density wall commonly used in laser indirect drive fusion research. The details of the simulations and their implications and suggestions for wavelength scaling coupled with innovative hohlraum designs will be discussed.

  8. Quick and facile preparation of visible light-driven TiO2 photocatalyst with high absorption and photocatalytic activity.

    Science.gov (United States)

    Yang, Yucheng; Zhang, Ting; Le, Ling; Ruan, Xuefeng; Fang, Pengfei; Pan, Chunxu; Xiong, Rui; Shi, Jing; Wei, Jianhong

    2014-11-13

    Self-doping TiO2 has recently attracted considerable attention for its high photocatalytic activity under visible-light irradiation. However, the literature reported synthetic methods until now were very time-consuming. In this study, we establish a quick and facile method for obtaining self-doping TiO2 with the use of directly treated commercial P25 at a desired temperature for only 5 min through spark plasma sintering technology. With the using of this method, the modified P25 samples exhibit significantly high photoelectric and photocatalytic performance. Furthermore, the sample prepared at 600 °C exhibits the optimum catalytic activity. The photodegradation and H2 evolution rates of this samples are significantly higher than those of unmodified P25 sample under visible-light irradiation. The physical origin of the visible-light absorption for the modified P25 samples is investigated in detail according to their structural, optical, and electronic properties. This work will provide a quick and facile method for the large-scale synthesis of visible-light driven photocatalyst for practical applications.

  9. Comparison of Bond Strength of Metal and Ceramic Brackets Bonded with Conventional and High-Power LED Light Curing Units.

    Science.gov (United States)

    Chalipa, Javad; Jalali, Yasamin Farajzadeh; Gorjizadeh, Fatemeh; Baghaeian, Pedram; Hoseini, Mohammad Hashem; Mortezai, Omid

    2016-11-01

    The aim of this study was to evaluate the effect of conventional and high-power light emitting diode (LED) light curing units on shear bond strength (SBS) of metal and ceramic brackets to tooth surface. Forty sound bovine maxillary central incisors were used for the study. The teeth were divided into four groups (n=10). Teeth surfaces were etched with 37% phosphoric acid for 20 seconds. After applying a uniform layer of adhesive primer on the etched enamel, composite was placed on the base of brackets. The samples were light cured according to the manufacturer's instructions and thermocycled. The SBS was measured. The failure mode was scored using the adhesive remnant index (ARI). The mean SBS of samples in groups A (high-power LED, metal bracket), B (high-power LED, ceramic bracket), C (conventional LED, metal bracket) and D (conventional LED, ceramic bracket) was 23.1±3.69, 10.7±2.06, 24.92±6.37 and 10.74±3.18MPa, respectively. The interaction effect of type of LED unit (high-power/conventional) and bracket type on SBS was not statistically significant (P=0.483). In general, type of LED unit did not affect SBS. Type of bracket significantly affected SBS (Pbracket. The obtained SBS is the same for both bracket types by use of high-power and conventional LED light curing units. Regardless of the type of LED unit, SBS of ceramic brackets was significantly lower than that of metal brackets.

  10. A simple fiber-optic microprobe for high resolution light measurements: application in marine sediment

    Science.gov (United States)

    Jorgensen, B. B.; Des Marais, D. J.

    1986-01-01

    A fiber-optic microphobe is described which is inexpensive and simple to build and use. It consists of an 80-micrometers optical fiber which at the end is tapered down to a rounded sensing tip of 20-30-micrometers diameter. The detector is a hybrid photodiode/amplifier. The probe has a sensitivity of 0.01 microEinst m-2 s-1 and a spectral range of 300-1,100 nm. Spectral light gradients were measured in fine-grained San Francisco Bay sediment that had an undisturbed diatom coating on the surface. The photic zone of the mud was only 0.4 mm deep. Measured in situ spectra showed extinction maxima at 430-520, 620-630, 670, and 825-850 nm due to absorption by chlorophyll a, carotenoids, phycocyanin, and bacterio-chlorophyll a. Maximum light penetration in the visible range was found in both the violet and the red or = 700 nm.

  11. A single molecule as a high-fidelity photon gun for producing intensity-squeezed light

    Science.gov (United States)

    Chu, Xiao-Liu; Götzinger, Stephan; Sandoghdar, Vahid

    2017-01-01

    A two-level atom cannot emit more than one photon at a time. As early as the 1980s, this quantum feature was identified as a gateway to 'single-photon sources', where a regular excitation sequence would create a stream of light particles with photon number fluctuations below the shot noise. Such an intensity-squeezed beam of light would be desirable for a range of applications, such as quantum imaging, sensing, enhanced precision measurements and information processing. However, experimental realizations of these sources have been hindered by large losses caused by low photon-collection efficiencies and photophysical shortcomings. By using a planar metallodielectric antenna applied to an organic molecule, we demonstrate the most regular stream of single photons reported to date. The measured intensity fluctuations were limited by our detection efficiency and amounted to 2.2 dB squeezing.

  12. High pressure near infrared study of the mutated light-harvesting complex LH2

    Directory of Open Access Journals (Sweden)

    Braun P.

    2005-01-01

    Full Text Available The pressure sensitivities of the near infrared spectra of the light-harvesting (LH2 complex and a mutant complex with a simplified BChl-B850 binding pocket were compared. In the mutant an abrupt change in the spectral properties occurred at 250 MPa, which was not observed with the native sample. Increased disorder due to collapse of the chromophore pocket is suggested.

  13. High-performance cathode elements for gas-discharge light sources

    Directory of Open Access Journals (Sweden)

    Sevastyanov V. V.

    2009-02-01

    Full Text Available Application of cathode elements of the arc-discharge activator made on the basis of developed material — alloy of iridium and rare-earth metals (of cerium group — has been suggested. The working samples of arc lamps have been produced and tested. The location of metal-alloy cathode has been optimized. The tests demonstrated, that after 4500 hours of work the lighting-up and glowing parameters of such lamps remained stable.

  14. Effect of oxygen at low and high light intensities on the growth of Neochloris oleoabundans

    NARCIS (Netherlands)

    Sousa, C.A.; Compadre, A.; Vermuë, M.H.; Wijffels, R.H.

    2013-01-01

    The effect of partial oxygen pressure on growth of Neochloris oleoabundans was studied at near-saturating light intensity in a fully-controlled photobioreactor. At the partial oxygen pressures tested (PO2=0.24; 0.42; 0.63; 0.84 bar), the specific growth rate was 1.36; 1.16; 0.93 and 0.68 day-1,

  15. Concepts for a low emittance-high capacity storage ring for the Diamond Light Source

    CERN Document Server

    Bartolini, Riccardo; Evans, Gwyndaf; Sawhney, Kawal; Zegenhagen, Joerg

    2017-01-01

    The Diamond Light Source is investigating several paths for a possible machine upgrade to Diamond II. The exercise is driven by a joint assessment of the science capabilities opened by a very low emittance ring and the machine design that will underpin them. The consultation is made on a beamline-by-beamline basis and has highlighted a significant preference for lattices that combine both a low emittance and large capacity for IDs.

  16. Baking Light

    DEFF Research Database (Denmark)

    Tamke, Martin

    2005-01-01

    decisions. Display quality, comfortable navigation and realistic illumination are crucial ingredients here. Light is one of the principal elements in architectural design, so design reviews must enable the architect to judge the quality of his design in this respect. Realistic light simulations, e.g. via...... radiosity algorithms, are no longer the domain of high-end graphic workstations. Today’s off-the-shelf hardware and 3D-software provide the architect with high-quality tools to simulate physically correct light distributions. But the quality and impression of light is hard to judge by looking at still...... practical experiences with global-light-simulations. We share results which we think are helpful to others, and we highlight areas where further research is necessary....

  17. Improvement in the light sensitivity of the ultrahigh-speed high-sensitivity CCD with a microlens array

    Science.gov (United States)

    Hayashida, T.,; Yonai, J.; Kitamura, K.; Arai, T.; Kurita, T.; Tanioka, K.; Maruyama, H.; Etoh, T. Goji; Kitagawa, S.; Hatade, K.; Yamaguchi, T.; Takeuchi, H.; Iida, K.

    2008-02-01

    We are advancing the development of ultrahigh-speed, high-sensitivity CCDs for broadcast use that are capable of capturing smooth slow-motion videos in vivid colors even where lighting is limited, such as at professional baseball games played at night. We have already developed a 300,000 pixel, ultrahigh-speed CCD, and a single CCD color camera that has been used for sports broadcasts and science programs using this CCD. However, there are cases where even higher sensitivity is required, such as when using a telephoto lens during a baseball broadcast or a high-magnification microscope during science programs. This paper provides a summary of our experimental development aimed at further increasing the sensitivity of CCDs using the light-collecting effects of a microlens array.

  18. Testing quantum mechanics in non-Minkowski space-time with high power lasers and 4(th) generation light sources.

    Science.gov (United States)

    Crowley, B J B; Bingham, R; Evans, R G; Gericke, D O; Landen, O L; Murphy, C D; Norreys, P A; Rose, S J; Tschentscher, Th; Wang, C H-T; Wark, J S; Gregori, G

    2012-01-01

    A common misperception of quantum gravity is that it requires accessing energies up to the Planck scale of 10¹⁹ GeV, which is unattainable from any conceivable particle collider. Thanks to the development of ultra-high intensity optical lasers, very large accelerations can be now the reached at their focal spot, thus mimicking, by virtue of the equivalence principle, a non Minkowski space-time. Here we derive a semiclassical extension of quantum mechanics that applies to different metrics, but under the assumption of weak gravity. We use our results to show that Thomson scattering of photons by uniformly accelerated electrons predicts an observable effect depending upon acceleration and local metric. In the laboratory frame, a broadening of the Thomson scattered x ray light from a fourth generation light source can be used to detect the modification of the metric associated to electrons accelerated in the field of a high power optical laser.

  19. Characterizing Reversible Protein Association at Moderately High Concentration Via Composition-Gradient Static Light Scattering.

    Science.gov (United States)

    Some, Daniel; Pollastrini, Joseph; Cao, Shawn

    2016-08-01

    Analysis of weakly self-associating macromolecules at concentrations beyond a few g/L is challenging on account of the confounding effect of thermodynamic nonideality on the association signal. When the reversible association comprises only 1 or 2 oligomeric species in equilibrium with the monomer, the nonideality may be accounted for in a relatively rigorous manner, but if more association states are involved, the analysis becomes quite complex. We show that under reasonable assumptions, the nonideality in a composition-gradient static light scattering measurement may be accounted for in a simple fashion. The correction is applied to determining the stoichiometry and binding affinity of a protein previously characterized via sedimentation equilibrium and dynamic light scattering. The results of the new analysis are remarkably self-consistent and in line with the expectations for the form of self-association predicted previously from analysis of the surface residuals, establishing composition-gradient multi-angle static light scattering with nonideality corrections as a critical technology for characterizing associative interactions in concentrated solutions. Copyright © 2016 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  20. A Single-Stage High-Power-Factor Light-Emitting Diode (LED) Driver with Coupled Inductors for Streetlight Applications

    OpenAIRE

    Chun-An Cheng; Chien-Hsuan Chang; Hung-Liang Cheng; Ching-Hsien Tseng; Tsung-Yuan Chung

    2017-01-01

    This paper presents and implements a single-stage high-power-factor light-emitting diode (LED) driver with coupled inductors, suitable for streetlight applications. The presented LED driver integrates an interleaved buck-boost power factor correction (PFC) converter with coupled inductors and a half-bridge-type series-resonant converter cascaded with a full-bridge rectifier into a single-stage power conversion circuit. Coupled inductors inside the interleaved buck-boost PFC converter sub-circ...

  1. Thermohydraulische Auslegung des Zwischenüberhitzers eines High Performance Light Water Reactors. (KIT Scientific Reports ; 7595)

    OpenAIRE

    Herbell, Heiko

    2011-01-01

    Der High Performance Light Water Reactor (HPLWR) ist ein Reaktorkonzept der IV. Generation (25 MPa und 500°C am Reaktoraustritt). In der vorliegenden Arbeit wurden numerische Untersuchungen über den Einfluss von Auftriebseffekten auf gekühlte Rohrströmungen von Fluiden mit überkritischem Druck durchgeführt. Für das HPLWR Konzept werden eine Auslegung und thermodynamische Optimierung des Zwischenüberhitzers unter Berücksichtigung der Turbinenauslegung vorgestellt.

  2. Eosin Y-sensitized artificial photosynthesis by highly efficient visible-light-driven regeneration of nicotinamide cofactor.

    Science.gov (United States)

    Lee, Sahng Ha; Nam, Dong Heon; Kim, Jae Hong; Baeg, Jin-Ook; Park, Chan Beum

    2009-07-06

    Dye-sensitized photosynthesis: Eosin Y (EY), a dye photosensitizer, works efficiently as a molecular photoelectrode by catalyzing the visible-light-driven electron-transfer reaction for efficient regeneration of NADH through a photosensitizer-electron relay dyad. Injection of the photosensitized electron resulted in highly accelerated regeneration of NADH, which can be used by glutamate dehydrogenase for the photosynthesis of L-glutamate.

  3. Involvement of thioredoxin y2 in the preservation of leaf methionine sulfoxide reductase capacity and growth under high light.

    Science.gov (United States)

    Laugier, Edith; Tarrago, Lionel; Courteille, Agathe; Innocenti, Gilles; Eymery, Françoise; Rumeau, Dominique; Issakidis-Bourguet, Emmanuelle; Rey, Pascal

    2013-03-01

    Methionine (Met) in proteins can be oxidized to two diastereoisomers of methionine sulfoxide, Met-S-O and Met-R-O, which are reduced back to Met by two types of methionine sulfoxide reductases (MSRs), A and B, respectively. MSRs are generally supplied with reducing power by thioredoxins. Plants are characterized by a large number of thioredoxin isoforms, but those providing electrons to MSRs in vivo are not known. Three MSR isoforms, MSRA4, MSRB1 and MSRB2, are present in Arabidopsis thaliana chloroplasts. Under conditions of high light and long photoperiod, plants knockdown for each plastidial MSR type or for both display reduced growth. In contrast, overexpression of plastidial MSRBs is not associated with beneficial effects in terms of growth under high light. To identify the physiological reductants for plastidial MSRs, we analyzed a series of mutants deficient for thioredoxins f, m, x or y. We show that mutant lines lacking both thioredoxins y1 and y2 or only thioredoxin y2 specifically display a significantly reduced leaf MSR capacity (-25%) and growth characteristics under high light, related to those of plants lacking plastidial MSRs. We propose that thioredoxin y2 plays a physiological function in protein repair mechanisms as an electron donor to plastidial MSRs in photosynthetic organs. © 2012 Blackwell Publishing Ltd.

  4. High temperatures and absence of light affect the hatching of resting eggs of Daphnia in the tropics

    Directory of Open Access Journals (Sweden)

    Thécia A.S.V. Paes

    2016-03-01

    Full Text Available Temperature and light are acknowledged as important factors for hatching of resting eggs. The knowledge of how they affect hatching rates of this type of egg is important for the comprehension of the consequences of warming waters in recolonization of aquatic ecosystems dependent on dormant populations. This study aimed at comparing the influence of different temperature and light conditions on hatching rates of Daphnia ambigua andDaphnia laevis resting eggs from tropical environments. The ephippia were collected in the sediment of three aquatic ecosystems, in southeastern Brazil. For each lake, the resting eggs were exposed to temperatures of 20, 24, 28 and 32 °C, under light (12 h photoperiod and dark conditions. The results showed that the absence of light and high temperatures have a negative influence on the hatching rates. Statistical differences for hatching rates were also found when comparing the studied ecosystems (ranging from 0.6 to 31%, indicating the importance of local environmental factors for diapause and maintenance of active populations.

  5. Silicon-Light: a European project aiming at high efficiency thin film silicon solar cells on foil

    Directory of Open Access Journals (Sweden)

    Soppe W.

    2014-07-01

    Full Text Available In the European project Silicon-Light we developed concepts and technologies to increase conversion efficiencies of thin film silicon solar cells on foil. Main focus was put on improved light management, using NIL for creating light scattering textures, improved TCOs using sputtering, and improved silicon absorber material made by PECVD. On foil we achieved initial cell efficiencies of 11% and on rigid substrates stable efficiencies of 11.6% were achieved. Finally, the project demonstrated the industrial scale feasibility of the developed technologies and materials. Cost of ownership calculations showed that implementation of these technologies on large scale would enable the production of these high efficiency solar modules at manufacturing cost of 0.65 €/Wp with encapsulation costs (0.20 €/Wp being the dominant costs. Life cycle analysis showed that large scale production of modules based on the technologies developed in Silicon-Light would have an energy payback time of 0.85 years in Central European countries.

  6. Starch and lipid accumulation in eight strains of six Chlorella species under comparatively high light intensity and aeration culture conditions.

    Science.gov (United States)

    Takeshita, Tsuyoshi; Ota, Shuhei; Yamazaki, Tomokazu; Hirata, Aiko; Zachleder, Vilém; Kawano, Shigeyuki

    2014-04-01

    The microalgae family Chlorella species are known to accumulate starch and lipids. Although nitrogen or phosphorous deficiencies promote starch and lipids formation in many microalgae, these deficiencies also limit their growth and productivity. Therefore, the Chlorellaceae strains were attempted to increase starch and lipids productivity under high-light-intensity conditions (600-μmol photons m(-2)s(-1)). The 12:12-h light-dark (LD) cycle conditions elicited more stable growth than the continuous light (LL) conditions, whereas the starch and lipids yields increased in LL conditions. The amount of starch and lipids per cell increased in Chlorella viscosa and Chlorella vulgaris in sulfur-deficient medium, and long-chain fatty acids with 20 or more carbon atoms accumulated in cells grown in sulfur-deficient medium. Accumulation of starch and lipids was investigated in eight strains. The accumulation was strain-dependent, and varied according to the medium and light conditions. Five of the eight Chlorella strains exhibited similar accumulation patterns. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. High CO2 concentration increases relative leaf carbon gain under dynamic light in Dipterocarpus sublamellatus seedlings in a tropical rain forest, Malaysia.

    Science.gov (United States)

    Tomimatsu, Hajime; Iio, Atsuhiro; Adachi, Minaco; Saw, Leng-Guan; Fletcher, Christine; Tang, Yanhong

    2014-09-01

    Understory plants in tropical forests often experience a low-light environment combined with high CO2 concentration. We hypothesized that the high CO2 concentration may compensate for leaf carbon loss caused by the low light, through increasing light-use efficiency of both steady-state and dynamic photosynthetic properties. To test the hypothesis, we examined CO2 gas exchange in response to an artificial lightfleck in Dipterocarpus sublamellatus Foxw. seedlings under contrasting CO2 conditions: 350 and 700 μmol CO2 mol(-1) air in a tropical rain forest, Pasoh, Malaysia. Total photosynthetic carbon gain from the lightfleck was about double when subjected to the high CO2 when compared with the low CO2 concentration. The increase of light-use efficiency in dynamic photosynthesis contributed 7% of the increased carbon gain, most of which was due to reduction of photosynthetic induction to light increase under the high CO2. The light compensation point of photosynthesis decreased by 58% and the apparent quantum yield increased by 26% at the high CO2 compared with those at the low CO2. The study suggests that high CO2 increases photosynthetic light-use efficiency under both steady-state and fluctuating light conditions, which should be considered in assessing the leaf carbon gain of understory plants in low-light environments. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  8. Interactive effects of ambient temperature and light sources at high relative humidity on growth performance and blood physiological variables in broilers grown to 42 day of age

    Science.gov (United States)

    The interactive effects of ambient temperature and light sources at high relative humidity on growth performance and blood physiological reactions in broilers grown to 42 day of age were investigated. The experiment consisted of 2 levels (Moderate=21.1, High=26.7 °C) of temperatures and 2 light sour...

  9. Light Pipe Transporter for High-rise Office Building in Tropical Climate

    Directory of Open Access Journals (Sweden)

    Christopher Yii Sern Heng

    2016-01-01

    Full Text Available Daylight has known to bring benefits for human, psychologically and physiologically. It also provides better indoor environment quality and thus increase the performance and productivity of office workers as stated by Paevere (2009. However, due to economic reasons, the current practice of using deep open plan building has cause a dent to having daylight in the interior spaces, which cause a dependency on artificial lighting. Hence, to provide daylight in deep interior, light distribution system is needed. Although so, according to Hansen (2003, most of the systems can only illuminate up to 8m-10m depth. Therefore, light pipe (LP plays an essential role where it can illuminate up to 20m depth. LP’s efficiency depends on the 3 main components; collector, transporter and extractor. This research explores the effectiveness of horizontal LP through different type of transporter’s shapes which includes rectangular, triangular, square and semi-circle. Previous studies have shown differences of efficiency on the shaped while using vertical LP. This research’s analysis was done using a computer simulation, Integrated Environment Solution: Virtual Environment (IESVE, where DF of each shapes were compared to MS 1525:2007 benchmark. The viability of the software was also validated though an assessment with a physical scaled-model experiment that was conducted in an open car park in Universiti Teknologi Malaysia, Johor, Malaysia. The results from the simulation showed that semi-circle shaped transporter offered the same efficiency as rectangular shaped. These findings will promote the usage of LP in buildings as it decreases the costing for LP.

  10. Optical light curve of the Crab nebula pulsar with high time resolution

    Energy Technology Data Exchange (ETDEWEB)

    Beskin, G.M.; Neizvestnyj, S.I.; Pimonov, A.A.; Plakhotnichenko, V.L.; Shvartsman, V.F. (AN SSSR, Nizhnij Arkhyz. Spetsial' naya Astrofizicheskaya Observatoriya)

    1983-01-01

    It is shown that there is no fine time structure in the averaged light curve of the Crab Nebula pulsar. Observations were made at the 6-m telescope in the R band with a resolution of 6 ..mu..s. At the time scale of the order of 10 ..mu..s the correspondinq restrictions on ..delta..I/I are 10% for the main pulse and 15% for the interpulse. The peaks of the main pulse and the interpulse are flattened with the characteristic widths of about 100 and 400 ..mu..s respectively at the 0.97 level of the maximum intensity.

  11. High energy transmission of Al2O3 doped with light transition metals

    KAUST Repository

    Schuster, Cosima

    2012-01-31

    The transmission of transparent colored ceramics based on Al2O3doped with light transition metals is measured in the visible and infrared range. To clarify the role of the dopands we perform ab initiocalculations. We discuss the electronic structure and present optical spectra obtained in the independent particle approximation. We argue that the gross spectral features of Co- and Ni-doped Al2O3 samples are described by our model, while the validity of the approach is limited for Cr-doped Al2O3.

  12. Study of High Fluence Radiation-induced Swelling and Hardening under Light Water Reactor Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Golubov, Stanislav I. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Barashev, Alexander V. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Stoller, Roger E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-09-01

    This report documents a comprehensive model that has been developed to enable simulations of microstructural evolution under the irradiation conditions typical of light water reactor (LWR) internal components. The model, which accounts cascade production of point defects and vacancy, interstitial faulted dislocation loops, interstitial clusters migrating one-dimensionally and the evolution of the network dislocation structure, has been parameterized to account damage accumulation in austenitic stainless steels. Nucleation and growth of an ensemble of cavities is based on accounting the residual and produced by irradiation He atoms and existence of the dislocation and production biases. Additional applications and potential future developments for the model are also discussed.

  13. Overview of Accelerator Physics Studies and High Level Software for the Diamond Light Source

    CERN Document Server

    Bartolini, Riccardo; Belgroune, Mahdia; Christou, Chris; Holder, David J; Jones, James; Kempson, Vince; Martin, Ian; Rowland, James H; Singh, Beni; Smith, Susan L; Varley, Jennifer Anne; Wyles, Naomi

    2005-01-01

    DIAMOND is a 3 GeV synchrotron light source under construction at Rutherford Appleton Laboratory in Oxfordshire (UK). The accelerators complex consists of a 100 MeV LINAC, a full energy booster and a 3GeV storage ring with 22 straight sections available for IDs. Installation of all three accelerators has begun, and LINAC commissioning is due to start in Spring 2005. This paper will give an overview of the accelerator physics activity to produce final layouts and prepare for the commissioning of the accelerator complex. The DIAMOND facility is expected to be operational for users in 2007

  14. Generating high-peak-power structured lights in selectively pumped passively Q-switched lasers with astigmatic mode transformations

    Science.gov (United States)

    Chang, C. C.; Hsieh, Y. H.; Lee, C. Y.; Sung, C. L.; Tuan, P. H.; Tung, J. C.; Liang, H. C.; Chen, Y. F.

    2017-12-01

    Various high-order Hermite–Gaussian (HG) modes with high repetition rates and high peak powers are systematically generated by designing the cavity configuration to satisfy the criterion of the passive Q-switching. For the HG m,0 modes with the order m  =  1–9, the pulse repetition rate can exceed 100 kHz with peak power higher than 0.3 kW. For the HG m,m modes with the order m  =  1–10, the pulse repetition rate can be up to 37 kHz with peak power higher than 0.35 kW. Furthermore, the high-order HG beams is transformed by using an astigmatic mode converter to generate various structured lights with optical vortices. Experimental patterns of the transformed high-order HG beams in the propagation are theoretically analyzed and the phase structures are numerically manifested.

  15. Calculating light & lighting

    NARCIS (Netherlands)

    Nederhoff, E.M.; Marcelis, L.F.M.

    2010-01-01

    Lighting in a greenhouse is surrounded by questions. How much light to supply and when?. What intensity and light sum to aim for? Is it radiation, light growlight, PAR, photons or quanta? How much is joule, watt, lux?. What does wavelength, nanometer, spectrum, UV, IR and NIR mean?

  16. LightForce Photon-Pressure Collision Avoidance: Updated Efficiency Analysis Utilizing a Highly Parallel Simulation Approach

    Science.gov (United States)

    Stupl, Jan; Faber, Nicolas; Foster, Cyrus; Yang, Fan Yang; Nelson, Bron; Aziz, Jonathan; Nuttall, Andrew; Henze, Chris; Levit, Creon

    2014-01-01

    This paper provides an updated efficiency analysis of the LightForce space debris collision avoidance scheme. LightForce aims to prevent collisions on warning by utilizing photon pressure from ground based, commercial off the shelf lasers. Past research has shown that a few ground-based systems consisting of 10 kilowatt class lasers directed by 1.5 meter telescopes with adaptive optics could lower the expected number of collisions in Low Earth Orbit (LEO) by an order of magnitude. Our simulation approach utilizes the entire Two Line Element (TLE) catalogue in LEO for a given day as initial input. Least-squares fitting of a TLE time series is used for an improved orbit estimate. We then calculate the probability of collision for all LEO objects in the catalogue for a time step of the simulation. The conjunctions that exceed a threshold probability of collision are then engaged by a simulated network of laser ground stations. After those engagements, the perturbed orbits are used to re-assess the probability of collision and evaluate the efficiency of the system. This paper describes new simulations with three updated aspects: 1) By utilizing a highly parallel simulation approach employing hundreds of processors, we have extended our analysis to a much broader dataset. The simulation time is extended to one year. 2) We analyze not only the efficiency of LightForce on conjunctions that naturally occur, but also take into account conjunctions caused by orbit perturbations due to LightForce engagements. 3) We use a new simulation approach that is regularly updating the LightForce engagement strategy, as it would be during actual operations. In this paper we present our simulation approach to parallelize the efficiency analysis, its computational performance and the resulting expected efficiency of the LightForce collision avoidance system. Results indicate that utilizing a network of four LightForce stations with 20 kilowatt lasers, 85% of all conjunctions with a

  17. Highly efficient visible light photocatalysis of novel CuS/ZnO heterostructure nanowire arrays.

    Science.gov (United States)

    Lee, Mikyung; Yong, Kijung

    2012-05-17

    Here, a facile approach for the fabrication of CuS nanoparticle (NP)/ZnO nanowire (NW) heterostructures on a mesh substrate through a simple two-step solution method is demonstrated. Successive ionic layer adsorption and reaction (SILAR) was employed to uniformly deposit CuS NPs on the hydrothermally grown ZnO NW array. The synthesized CuS/ZnO heterostructure NWs exhibited superior photocatalytic activity under visible light compared to bare ZnO NWs. This strong photocatalytic activity under visible light is due to the interfacial charge transfer (IFCT) from the valence band of the ZnO NW to the CuS NP, which reduces CuS to Cu(2)S. After repeated cycles of photodecolorization of Acid Orange 7 (AO7), the photocatalytic behavior of CuS/ZnO heterostructure NWs exhibited no significant loss of activity. Furthermore, our CuS/ZnO NWs/mesh photocatalyst floats in solution via partial superhydrophobic modification of the NWs.

  18. High photoactive and visible-light responsive graphene/titanate nanotubes photocatalysts: preparation and characterization.

    Science.gov (United States)

    Qianqian, Zhai; Tang, Bo; Guoxin, Hu

    2011-12-30

    A series of graphene/titanate nanotubes (TNTs) photocatalysts using graphene and nanoscale TiO(2) or P25 as original materials were fabricated by hydrothermal method. Both low hydrothermal temperature and proper amount of graphene are propitious to better photoactivity. The photocatalytic activities of these nanocomposites far exceed that of P25, pure TNTs and reported TiO(2)-based nanocomposites for the degradation of Rhodamine-B under visible-light irradiation. These prepared photocatalysts were characterized by TEM, XRD, XPS, BET, FTIR and UV-vis diffuse reflection spectra, and the results indicate that the outstanding photoactivities in visible-light region result from sensitization effect of graphene rather than impurity level in the band gap of TNTs. Furthermore, large BET surface areas of these photocatalysts (almost 10 times larger than that of previously reported graphene/TiO(2) nanoparticles) evidently enhance their absorption abilities and photocatalytic performances (the rate constants of degrading Rhodamine-B are at least 5 times higher than that of previously reported photocatalysts). These photocatalysts show good stability, and their photoactivities do not obviously decrease after four times of repeated uses. A detailed photocatalytic mechanism is suggested, as well. Copyright © 2011 Elsevier B.V. All rights reserved.

  19. High-Fidelity Modelling Methodology of Light-Limited Photosynthetic Production in Microalgae.

    Directory of Open Access Journals (Sweden)

    Andrea Bernardi

    Full Text Available Reliable quantitative description of light-limited growth in microalgae is key to improving the design and operation of industrial production systems. This article shows how the capability to predict photosynthetic processes can benefit from a synergy between mathematical modelling and lab-scale experiments using systematic design of experiment techniques. A model of chlorophyll fluorescence developed by the authors [Nikolaou et al., J Biotechnol 194:91-99, 2015] is used as starting point, whereby the representation of non-photochemical-quenching (NPQ process is refined for biological consistency. This model spans multiple time scales ranging from milliseconds to hours, thus calling for a combination of various experimental techniques in order to arrive at a sufficiently rich data set and determine statistically meaningful estimates for the model parameters. The methodology is demonstrated for the microalga Nannochloropsis gaditana by combining pulse amplitude modulation (PAM fluorescence, photosynthesis rate and antenna size measurements. The results show that the calibrated model is capable of accurate quantitative predictions under a wide range of transient light conditions. Moreover, this work provides an experimental validation of the link between fluorescence and photosynthesis-irradiance (PI curves which had been theoricized.

  20. High-Fidelity Modelling Methodology of Light-Limited Photosynthetic Production in Microalgae

    Science.gov (United States)

    Meneghesso, Andrea; Morosinotto, Tomas; Chachuat, Benoît; Bezzo, Fabrizio

    2016-01-01

    Reliable quantitative description of light-limited growth in microalgae is key to improving the design and operation of industrial production systems. This article shows how the capability to predict photosynthetic processes can benefit from a synergy between mathematical modelling and lab-scale experiments using systematic design of experiment techniques. A model of chlorophyll fluorescence developed by the authors [Nikolaou et al., J Biotechnol 194:91–99, 2015] is used as starting point, whereby the representation of non-photochemical-quenching (NPQ) process is refined for biological consistency. This model spans multiple time scales ranging from milliseconds to hours, thus calling for a combination of various experimental techniques in order to arrive at a sufficiently rich data set and determine statistically meaningful estimates for the model parameters. The methodology is demonstrated for the microalga Nannochloropsis gaditana by combining pulse amplitude modulation (PAM) fluorescence, photosynthesis rate and antenna size measurements. The results show that the calibrated model is capable of accurate quantitative predictions under a wide range of transient light conditions. Moreover, this work provides an experimental validation of the link between fluorescence and photosynthesis-irradiance (PI) curves which had been theoricized. PMID:27055271

  1. Influence of pitting defects on quality of high power laser light field

    Science.gov (United States)

    Ren, Huan; Zhang, Lin; Yang, Yi; Shi, Zhendong; Ma, Hua; Jiang, Hongzhen; Chen, Bo; Yang, XiaoYu; Zheng, Wanguo; Zhu, Rihong

    2018-01-01

    With the split-step-Fourier-transform method for solving the nonlinear paraxial wave equation, the intensity distribution of the light field when the pits diameter or depth change is obtained by using numerical simulation, include the intensity distribution inside optical element, the beam near-field, the different distances behind the element and the beam far-field. Results show that with the increase of pits diameter or depth, the light field peak intensity and the contrast inside of element corresponding enhancement. The contrast of the intensity distribution of the rear surface of the element will increase slightly. The peak intensity produced by a specific location element downstream of thermal effect will continue to increase, the damage probability in optics placed here is greatly increased. For the intensity distribution of the far-field, increase the pitting diameter or depth will cause the focal spot intensity distribution changes, and the energy of the spectrum center region increase constantly. This work provide a basis for quantitative design and inspection for pitting defects, which provides a reference for the design of optical path arrangement.

  2. Microemulsion synthesis, characterization of highly visible light responsive rare earth-doped Bi2O3.

    Science.gov (United States)

    Wu, Shuxing; Fang, Jianzhang; Xu, Xiaoxin; Liu, Zhang; Zhu, Ximiao; Xu, Weicheng

    2012-01-01

    In this paper, Bi(2)O(3) and rare earth (La, Ce)-doped Bi(2)O(3) visible-light-driven photocatalysts were prepared in a Triton X-100/n-hexanol/cyclohexane/water reverse microemulsion. The resulting materials were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) surface area, photoluminescence spectra (PLS) and UV-Vis diffuse reflectance spectroscopy. The XRD patterns of the as-prepared catalysts calcined at 500 °C exhibited only the characteristic peaks of monoclinic α-Bi(2)O(3). PLS analysis implied that the separation efficiency for electron-hole has been enhanced when Bi(2)O(3) was doped with rare earth. UV-Vis diffuse reflectance spectroscopy measurements presented an extension of light absorption into the visible region. The photocatalytic activity of the samples was evaluated by degradation of methyl orange (MO) and 2,4-dichlorophenol (2,4-DCP). The results displayed that the photocatalytic activity of rare earth-doped Bi(2)O(3) was higher than that of dopant-free Bi(2)O(3). The optimal dopant amount of La or Ce was 1.0 mol%. And the mechanisms of influence on the photocatalytic activity of the catalysts were discussed. © 2012 Wiley Periodicals, Inc. Photochemistry and Photobiology © 2012 The American Society of Photobiology.

  3. Nano-ferrites for water splitting: Unprecedented high photocatalytic hydrogen production under visible light

    KAUST Repository

    Mangrulkar, Priti A.

    2012-01-01

    In the present investigation, hydrogen production via water splitting by nano-ferrites was studied using ethanol as the sacrificial donor and Pt as co-catalyst. Nano-ferrite is emerging as a promising photocatalyst with a hydrogen evolution rate of 8.275 μmol h -1 and a hydrogen yield of 8275 μmol h -1 g -1 under visible light compared to 0.0046 μmol h -1 for commercial iron oxide (tested under similar experimental conditions). Nano-ferrites were tested in three different photoreactor configurations. The rate of hydrogen evolution by nano-ferrite was significantly influenced by the photoreactor configuration. Altering the reactor configuration led to sevenfold (59.55 μmol h -1) increase in the hydrogen evolution rate. Nano-ferrites have shown remarkable stability in hydrogen production up to 30 h and the cumulative hydrogen evolution rate was observed to be 98.79 μmol h -1. The hydrogen yield was seen to be influenced by several factors like photocatalyst dose, illumination intensity, irradiation time, sacrificial donor and presence of co-catalyst. These were then investigated in detail. It was evident from the experimental data that nano-ferrites under optimized reaction conditions and photoreactor configuration could lead to remarkable hydrogen evolution activity under visible light. Temperature had a significant role in enhancing the hydrogen yield. © 2012 The Royal Society of Chemistry.

  4. C3 photosynthesis in the desert plant Rhazya stricta is fully functional at high temperatures and light intensities.

    Science.gov (United States)

    Lawson, Tracy; Davey, Phillip A; Yates, Steven A; Bechtold, Ulrike; Baeshen, Mohammed; Baeshen, Nabih; Mutwakil, Mohammed Z; Sabir, Jamal; Baker, Neil R; Mullineaux, Philip M

    2014-02-01

    The C3 plant Rhazya stricta is native to arid desert environment zones, where it experiences daily extremes of heat, light intensity (PAR) and high vapour pressure deficit (VPD). We measured the photosynthetic parameters in R. stricta in its native environment to assess the mechanisms that permit it to survive in these extreme conditions. Infrared gas exchange analysis examined diel changes in assimilation (A), stomatal conductance (gs ) and transpiration (E) on mature leaves of R. stricta. A/ci analysis was used to determine the effect of temperature on carboxylation capacity (Vc,max ) and the light- and CO2 -saturated rate of photosynthesis (Amax ). Combined chlorophyll fluorescence and gas exchange light response curve analysis at ambient and low oxygen showed that both carboxylation and oxygenation of Rubisco acted as the major sinks for the end products of electron transport. Physiological analysis in conjunction with gene expression analysis suggested that there are two isoforms of Rubisco activase which may provide an explanation for the ability of R. stricta to maintain Rubisco function at high temperatures. The potential to exploit this ability to cope with extreme temperatures is discussed in the context of future crop improvement. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

  5. Stable White Light Electroluminescence from Highly Flexible Polymer/ZnO Nanorods Hybrid Heterojunction Grown at 50°C

    Directory of Open Access Journals (Sweden)

    Zainelabdin A

    2010-01-01

    Full Text Available Abstract Stable intrinsic white light–emitting diodes were fabricated from c-axially oriented ZnO nanorods (NRs grown at 50°C via the chemical bath deposition on top of a multi-layered poly(9,9-dioctylfluorene-co–N-(4-butylpheneylaminediphenylamine/poly(9,9dioctyl-fluorene deposited on PEDOT:PSS on highly flexible plastic substrate. The low growth temperature enables the use of a variety of flexible plastic substrates. The fabricated flexible white light–emitting diode (FWLED demonstrated good electrical properties and a single broad white emission peak extending from 420 nm and up to 800 nm combining the blue light emission of the polyflourene (PFO polymer layer with the deep level emission (DLEs of ZnO NRs. The influence of the temperature variations on the FWLED white emissions characteristics was studied and the devices exhibited high operation stability. Our results are promising for the development of white lighting sources using existing lighting glass bulbs, tubes, and armature technologies.

  6. Influence of high latitude light conditions on sensory quality and contents of health and sensory-related compounds in swede roots (Brassica napus L. ssp. rapifera Metzg.).

    Science.gov (United States)

    Mølmann, Jørgen Ab; Hagen, Sidsel Fiskaa; Bengtsson, Gunnar B; Johansen, Tor J

    2018-02-01

    Vegetable growers in Arctic areas must increasingly rely on market strategies based on regional origin and product quality. Swede roots (rutabaga) were grown in a phytotron to investigate the effect of high latitude light conditions on sensory quality and some health and sensory-related compounds. Experimental treatments included modifications of 24 h natural day length (69° 39' N) by moving plants at daily intervals to dark chambers with either no light, fluorescent growth light and/or low intensity photoperiod extension. Shortening the photosynthetic light period to 12 h produced smaller roots than 15.7 h and 18 h, with highest scores for bitter and sulfur taste, and lowest scores for sweetness, acidic taste and fibrousness. The photoperiod in combination with the photosynthetic light period also had an influence on glucosinolate (GLS) contents, with lowest concentrations in 24 h natural light and highest in 12 h natural light. Concentrations of vitamin C, glucose, fructose and sucrose were not significantly influenced by any of the treatments. High latitude light conditions, with long photosynthetic light periods and 24 h photoperiod, can enhance sweet/less bitter taste and reduce GLS contents in swede roots, compared to growth under short day conditions. This influence of light conditions on eating quality may benefit marketing of regional products from high latitudes. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  7. Influence of various red doping materials on the photoelectric performance of highly efficient organic light-emitting devices

    Science.gov (United States)

    Wang, Ching-Wu; Li, Jian-Feng; Kuo, Wen-Fa

    2002-09-01

    The influence of various red doping materials on the photoelectric performance of highly efficient organic light emitting diodes (OLEDs) were systematically investigated. The multilayerd red-light OLEDs fabricated in this work have the structure of ITO/m-MTDATA/NPB/Alq3:MGAg. Three different doping materials, including 4-(dicyanomethylene)-2-t-butyl-6(1,1,7,7-tetra-methyl-ljulolidyl-9-enyl)-4H-pyran, 4-Dicyanomethyl-lene-2-methyl-6-[2-(2,3,6,7-tetrahydro-1H,5H-benzo quinoliz-in-8-yl)vinyl]4H-pyran) (DCM2), and Nile Red (NIR), were adopted. Compared with the various red-doped OLEDs, the highest luminance occureed in DCM2-doped OLED. Evidence showed that the co-existence of exciton energy transfer and carrier trapping processes in DCM2-doped OLED is the main reason leading the highest luminance occurred in that device.

  8. Reflective dual-mode liquid crystal display possessing low power consumption and high contrast ratio under ambient light.

    Science.gov (United States)

    Kim, Taehyung; Lee, Joong Ha; Yoon, Tae-Hoon; Choi, Suk-Won

    2012-07-02

    We propose a reflective dual-mode liquid crystal display (RD-LCD) which has advantages of long memory retention time and high contrast ratio. The proposed device adopts ideal bistable characteristics, a cell thickness over pitch (d/p) of 0.25. It can realize long memory retention time, thereby reducing power consumption. In addition, an optical configuration for the RD-LCD makes low light leakages at dark state and shows good dispersion characteristics in both dark and bright states over the entire visible ranges. We experimentally confirmed retention time over 6 months in memory mode and memory and dynamic contrast ratios of 47:1 and 43:1 under ambient light, respectively. As a result, the proposed RD-LCD demonstrates convincingly that it is a candidate for green display.

  9. Efficiency roll-off suppression in organic light-emitting diodes at high current densities using gold bowtie nanoantennas

    Science.gov (United States)

    Zhao, Yukun; Yun, Feng; Wu, Zhaoxin; Li, Yufeng; Jiao, Bo; Huang, Yaping; Li, Sanfeng; Feng, Lungang; Guo, Maofeng; Ding, Wen; Zhang, Ye; Dou, Juan

    2016-02-01

    In this study, large-scale gold (Au) bowtie nanoantennas have been utilized to suppress the efficiency roll-off in organic light-emitting diodes (OLEDs) numerically and experimentally. Compared with the OLED without nanoantennas, the experimental roll-off ratio of the OLED with Au bowtie nanoantennas significantly decreases from 59.4 to 51.3% at a high current density of 1000 mA/cm2. We attribute the roll-off suppression to the localized surface plasmon (LSP) effect, which leads to a shorter radiative lifetime. The insufficient coupling between radiated light and LSP resonance could also be improved by a strong resonance coupling between the tips of bowtie nanoantennas.

  10. Complete Control of Polarization and Phase of Light with High Efficiency and Sub-wavelength Spatial Resolution

    CERN Document Server

    Arbabi, Amir; Bagheri, Mahmood; Faraon, Andrei

    2014-01-01

    Meta-surfaces are planar structures that locally change polarization, phase, and amplitude of light, thus enabling flat, lithographically patterned free-space optical components with functionalities controlled by design. Several types of meta-surfaces have been reported, but low efficiency and the inability to provide simultaneous phase and polarization control have limited their applications. Here we demonstrate a platform based on high-contrast dielectric elliptical nano-posts providing complete and efficient control of polarization and phase with sub-wavelength spatial resolution. The unprecedented freedom in manipulating light not only enables realization of conventional free-space transmissive optical elements such as phase-plates, wave-plates and beam-splitters, but also elements with novel functionalities such as general polarization switchable phase holograms and arbitrary vector beam generators which will change the design paradigms for free-space optical systems.

  11. Variable domain structure of {kappa}IV human light chain len : high homology to the murine light chain McPC603.

    Energy Technology Data Exchange (ETDEWEB)

    Huang, D.-B.; Chang, C.-H.; Ainsworth, C.; Johnson, G.; Solomon, A.; Stevens, F. J.; Schiffer, M.; Center for Mechanistic Biology and Biotechnology; Univ. of Tennessee Medical Center

    1997-12-01

    Antibody light chains of the {kappa} subgroup are the predominant light chain component in human immune responses and are used almost exclusively in the antibody repertoire of mice. Human {kappa} light chains comprise four subgroups. To date, all crystallographic studies of human {kappa} light chains were carried out on proteins of the {kappa}I subgroup. The light chain produced by multiple myeloma patient Len, was of the {kappa}IV subgroup, it differed by only one residue from the germ-line gene encoded protein. The variable domain fragment of the light chain was crystallized from ammonium sulfate in space group C222{sub 1}. The crystal structure was determined by molecular replacement and refined at 1.95 Angstrom resolution to an R-factor of 0.15. Protein Len has six additional residues in its CDR1 segment compared to the {kappa}I proteins previously characterized. The {kappa}IV variable domain. Len, differs in only 23 of 113 residues from murine {kappa} light chain McPC603. The RMS deviation upon superimposing their {alpha}-carbons was 0.69 Angstrom. The CDR1 segment of the human and murine variable domains have the same length and conformation although their amino acid sequences differ in 5 out of 17 residues. Structural features were identified that could account for the significantly higher stability of the human {kappa}IV protein relative to its murine counterpart. This human {kappa}IV light chain structure is the closest human homolog to a murine light chain and can be expected to facilitate detailed structural comparisons necessary for effective humanization of murine antibodies.

  12. Polarized light imaging of birefringence and diattenuation at highresolution and high sensitivity

    CERN Document Server

    Mehta, Shalin B; Oldenbourg, Rudolf

    2013-01-01

    Polarized light microscopy provides unique opportunities for analyzing the molecular order in man-made and natural materials, including biological structures inside living cells, tissues, and whole organisms. 20 years ago, the LC-PolScope was introduced as a modern version of the traditional polarizing microscope enhanced by liquid crystal devices for the control of polarization, and by electronic imaging and digital image processing for fast and comprehensive image acquisition and analysis. The LC- PolScope is commonly used for birefringence imaging, analyzing the spatial and temporal variations of the differential phase delay in ordered and transparent materials. Here we describe an alternative use of the LC-PolScope for imaging the polarization dependent transmittance of dichroic materials. We explain the minor changes needed to convert the instrument between the two imaging modes, discuss the relationship between the quantities measured with either instrument, and touch on the physical connection between ...

  13. Electromagnetic Coupling Between High Intensity LHC Beams and the Synchrotron Radiation Monitor Light Extraction System

    CERN Document Server

    Andreazza, W; Bravin, E; Caspers, F; Garlasch`e, M; Gras, J; Goldblatt, A; Lefevre, T; Jones, R; Metral, E; Nosych, A; Roncarolo_, F; Salvant, B; Trad, G; Veness, R; Vollinger, C; Wendt, M

    2013-01-01

    The CERN LHC is equipped with two Synchrotron Radiation Monitor (BSRT) systems used to characterise transverse and longitudinal beam distributions. Since the end of the 2011 LHC run the light extraction system, based on a retractable mirror, has suffered deformation and mechanical failure that is correlated to the increase in beam intensity. Temperature probes have associated these observations to a strong heating of the mirror support with a dependence on the longitudinal bunch length and shape, indicating the origin as electromagnetic coupling between the beam and the structure. This paper combines all this information with the aim of characterising and improving the system in view of its upgrade during the current LHC shutdown. Beam-based observations are presented along with electromagnetic and thermomechanical simulations and complemented by laboratory measurements, including the study of the RF properties of different mirror bulk and coating materials.

  14. Efficiency of Launching Highly Confined Polaritons by Infrared Light Incident on a Hyperbolic Material.

    Science.gov (United States)

    Dai, Siyuan; Ma, Qiong; Yang, Yafang; Rosenfeld, Jeremy; Goldflam, Michael D; McLeod, Alex; Sun, Zhiyuan; Andersen, Trond I; Fei, Zhe; Liu, Mengkun; Shao, Yinming; Watanabe, Kenji; Taniguchi, Takashi; Thiemens, Mark; Keilmann, Fritz; Jarillo-Herrero, Pablo; Fogler, Michael M; Basov, D N

    2017-09-13

    We investigated phonon-polaritons in hexagonal boron nitride-a naturally hyperbolic van der Waals material-by means of the scattering-type scanning near-field optical microscopy. Real-space nanoimages we have obtained detail how the polaritons are launched when the light incident on a thin hexagonal boron nitride slab is scattered by various intrinsic and extrinsic inhomogeneities, including sample edges, metallic nanodisks deposited on its top surface, random defects, and surface impurities. The scanned tip of the near-field microscope is itself a polariton launcher whose efficiency proves to be superior to all the other types of polariton launchers we studied. Our work may inform future development of polaritonic nanodevices as well as fundamental studies of collective modes in van der Waals materials.

  15. A simple sub-nanosecond ultraviolet light pulse generator with high repetition rate and peak power.

    Science.gov (United States)

    Binh, P H; Trong, V D; Renucci, P; Marie, X

    2013-08-01

    We present a simple ultraviolet sub-nanosecond pulse generator using commercial ultraviolet light-emitting diodes with peak emission wavelengths of 290 nm, 318 nm, 338 nm, and 405 nm. The generator is based on step recovery diode, short-circuited transmission line, and current-shaping circuit. The narrowest pulses achieved have 630 ps full width at half maximum at repetition rate of 80 MHz. Optical pulse power in the range of several hundreds of microwatts depends on the applied bias voltage. The bias voltage dependences of the output optical pulse width and peak power are analysed and discussed. Compared to commercial UV sub-nanosecond generators, the proposed generator can produce much higher pulse repetition rate and peak power.

  16. Relativistic light-shift theory of few-electron systems: Heliumlike highly charged ions

    Science.gov (United States)

    Postavaru, O.; Scafes, A. C.

    2017-09-01

    The light-shift theory of many-electron systems in a laser field is described using the projection operators technique. In heavy ions, the electrons are tightly bound by the Coulomb potential of the nucleus, which prohibits ionization even by strong lasers. However, interaction with the monofrequent laser field leads to dynamic shifts of the electronic energy levels, and the process is treated by second-order time-dependent perturbation theory. In order to treat heliumlike systems, one decomposes the corresponding matrix elements into hydrogenlike matrix elements using the independent particle model. We are applying a fully relativistic description of the electronic states by means of the Dirac equation. Our formalism goes beyond the Stark long-wavelength dipole approximation and takes into account nondipole effects of retardation and interaction with the magnetic field components of the laser beam.

  17. Cyclometalated Iridium(III) Carbene Phosphors for Highly Efficient Blue Organic Light-Emitting Diodes.

    Science.gov (United States)

    Chen, Zhao; Wang, Liqi; Su, Sikai; Zheng, Xingyu; Zhu, Nianyong; Ho, Cheuk-Lam; Chen, Shuming; Wong, Wai-Yeung

    2017-11-22

    Five deep blue carbene-based iridium(III) phosphors were synthesized and characterized. Interestingly, one of them can be fabricated into deep blue, sky blue and white organic light-emitting diodes (OLEDs) through changing the host materials and exciton blocking layers. These deep and sky blue devices exhibit Commission Internationale de l'Éclairage (CIE) coordinates of (0.145, 0.186) and (0.152, 0.277) with external quantum efficiency (EQE) of 15.2% and 9.6%, respectively. The EQE of the deep blue device can be further improved up to 19.0% by choosing a host with suitable energy level of its lowest unoccupied molecular orbital (LUMO).

  18. High-Wattage Pulsed Irradiation of Linearly Polarized Near-Infrared Light to Stellate Ganglion Area for Burning Mouth Syndrome

    Directory of Open Access Journals (Sweden)

    Yukihiro Momota

    2014-01-01

    Full Text Available The purpose of this study was to apply high-wattage pulsed irradiation of linearly polarized near-infrared light to the stellate ganglion area for burning mouth syndrome (BMS and to assess the efficacy of the stellate ganglion area irradiation (SGR on BMS using differential time-/frequency-domain parameters (D parameters. Three patients with BMS received high-wattage pulsed SGR; the response to SGR was evaluated by visual analogue scale (VAS representing the intensity of glossalgia and D parameters used in heart rate variability analysis. High-wattage pulsed SGR significantly decreased the mean value of VAS in all cases without any adverse event such as thermal injury. D parameters mostly correlated with clinical condition of BMS. High-wattage pulsed SGR was safe and effective for the treatment of BMS; D parameters are useful for assessing efficacy of SGR on BMS.

  19. Museum lighting for golden artifacts, with low correlated color temperature, high color uniformity and high color rendering index, using diffusing color mixing of red, cyan, and white-light-emitting diodes

    DEFF Research Database (Denmark)

    Thorseth, Anders; Corell, Dennis Dan; Poulsen, Peter Behrensdorff

    2012-01-01

    at the Royal Danish Collection at Rosenborg Castle. Color mixing of red, cyan, and white LEDs was employed to achieve the spectral power distribution needed for the required CCT and a CRI above 90. Color uniformity is achieved by the use of a highly diffusing reflector. The system has shown energy saving above......Museum lighting presents challenges mainly due to the demand for precise color rendering and the damaging effects of radiation. Golden objects must normally be illuminated by the non-standard CCT of 2200 K. An LED system that conforms to these requirements has been developed and implemented...

  20. Rapid microwave-assisted synthesis of highly luminescent nitrogen-doped carbon dots for white light-emitting diodes

    Science.gov (United States)

    Wang, Yaling; Zheng, Jingxia; Wang, Junli; Yang, Yongzhen; Liu, Xuguang

    2017-11-01

    Highly luminescent nitrogen-doped carbon dots (N-CDs) were synthesized rapidly by one-step microwave-assisted hydrothermal method using citric acid as carbon source and ethylenediamine as dopant. The influences of reaction temperature, reaction time and raw material ratio on the fluorescence performance of N-CDs were investigated. Then N-CDs with the highest quantum yield were selected as fluorescent materials for fabricating white light-emitting diodes (LEDs). Highly luminescent N-CDs with the quantum yield of 75.96% and blue-to-red spectral composition of 51.48% were obtained at the conditions of 180 °C, 8 min and the molar ratio of citric acid to ethylenediamine 2:1. As-prepared highly luminescent N-CDs have an average size of 6.06 nm, possess extensive oxygen- and nitrogen-containing functional groups on their surface, and exhibit strong absorption in ultraviolet region. White LEDs based on the highly luminescent N-CDs emit warm white light with color coordinates of (0.42, 0.40) and correlated color temperature of 3416 K.

  1. Managing excitons for high performance hybrid white organic light-emitting diodes by using a simple planar heterojunction interlayer

    Science.gov (United States)

    Shi, Changsheng; Sun, Ning; Wu, Zhongbin; Chen, Jiangshan; Ahamad, Tansir; Alshehri, Saad M.; Ma, Dongge

    2018-01-01

    High performance hybrid white organic light-emitting diodes (WOLEDs) were fabricated by inserting a planar heterojunction interlayer between the fluorescent and phosphorescent emitting layers (EMLs). The maximum external quantum efficiency (EQE) of 19.3%, current efficiency of 57.1 cd A-1, and power efficiency (PE) of 66.2 lm W-1 were achieved in the optimized device without any light extraction enhancement. At the luminance of 1000 cd m-2, the EQE and PE remained as high as 18.9% and 60 lm W-1, respectively, showing the reduced efficiency-roll. In order to disclose the reason for such high performance, the distribution of excitons was analyzed by using ultra-thin fluorescent and phosphorescent layers as sensors. It was found that the heterojunction interlayer can efficiently separate the singlet and triplet excitons, preventing the triplet excitons from being quenched by the fluorescent emitter. The introduction of the heterojunction interlayer between the fluorescent and phosphorescent EMLs should offer a simple and efficient route to fabricate the high performance hybrid WOLEDs.

  2. High-Efficiency Perovskite Quantum-Dot Light-Emitting Devices by Effective Washing Process and Interfacial Energy Level Alignment.

    Science.gov (United States)

    Chiba, Takayuki; Hoshi, Keigo; Pu, Yong-Jin; Takeda, Yuya; Hayashi, Yukihiro; Ohisa, Satoru; Kawata, So; Kido, Junji

    2017-05-31

    All inorganic perovskites quantum dots (PeQDs) have attracted much attention for used in thin film display applications and solid-state lighting applications, owing to their narrow band emission with high photoluminescence quantum yields (PLQYs), color tunability, and solution processability. Here, we fabricated low-driving-voltage and high-efficiency CsPbBr3 PeQDs light-emitting devices (PeQD-LEDs) using a PeQDs washing process with an ester solvent containing butyl acetate (AcOBu) to remove excess ligands from the PeQDs. The CsPbBr3 PeQDs film washed with AcOBu exhibited a PLQY of 42%, and a narrow PL emission with a full width at half-maximum of 19 nm. We also demonstrated energy level alignment of the PeQD-LED in order to achieve effective hole injection into PeQDs from the adjacent hole injection layer. The PeQD-LED with AcOBu-washed PeQDs exhibited a maximum power efficiency of 31.7 lm W-1 and EQE of 8.73%. Control of the interfacial PeQDs through ligand removal and energy level alignment in the device structure are promising methods for obtaining high PLQYs in film state and high device efficiency.

  3. High light extraction efficiency into glass substrate in organic light-emitting diodes by patterning the cathode in graded superlattice with dual periodicity and dual basis

    Science.gov (United States)

    Hassan, Safaa; Lowell, David; Lin, Yuankun

    2017-06-01

    The newly discovered graded, superlattice photonic crystals with dual periodicity and dual basis present great opportunity for electromagnetic wave control in photonic devices. These graded superlattices can be holographically fabricated by eight beam interference lithography. We have computed, through electrodynamic simulation, the light extraction efficiency of planar, white organic light-emitting diodes where the Al cathode is patterned with the graded superlattice with dual basis. Two graded super-lattices with four-fold and two-fold symmetries are used to pattern the Al cathode. The decrease in power losses to surface plasmon and waveguide modes is explained by the varying plasmon path length and grating cycle, respectively, in the graded pattern. To the authors' best knowledge, the highest light extraction efficiency of 73.1% into the glass substrate in organic light-emitting diodes has been predicted through simulations.

  4. A Battery Powered Highly Efficient Exterior Lighting System Using Low Pressure Sodium Vapour Lamp for Use in Non-electrified Areas

    Science.gov (United States)

    Ray, Kalyankumar; Golder, Sujit; Mazumdar, Saswati

    Innumerous attempts to solve the problems of exterior lighting in non-electrified areas of India e.g. highways, hilly areas, rural areas of delta regions have been made in the last two decades. A solar powered lighting system with 11 watt or 18 watt Compact Fluorescent Lamps (CFL) have been mounted in street light fixtures at some places but insufficient amount of light do not always serve the required need of the users specially in foggy weather. This paper reports the development of a battery powered lighting system fitted with a 35 Watt Low Pressure Sodium Vapour (SOX) lamp. It is extremely beneficial in remote non-electrified areas for its far higher light output when fitted in street light or flood light fixtures. The battery may be charged from any non-conventional energy source and is connected to the electronic circuit, which operates at high frequency. The light output of this system fitted with a solar photovoltaic array (SPVA) and the corresponding battery power have been measured and the results have been reported in this paper. This high intensity lighting system has a wide application potential in developing countries throughout the world.

  5. Light and Electrically Induced Phase Segregation and Its Impact on the Stability of Quadruple Cation High Bandgap Perovskite Solar Cells.

    Science.gov (United States)

    Duong, The; Mulmudi, Hemant Kumar; Wu, YiLiang; Fu, Xiao; Shen, Heping; Peng, Jun; Wu, Nandi; Nguyen, Hieu T; Macdonald, Daniel; Lockrey, Mark; White, Thomas P; Weber, Klaus; Catchpole, Kylie

    2017-08-16

    Perovskite material with a bandgap of 1.7-1.8 eV is highly desirable for the top cell in a tandem configuration with a lower bandgap bottom cell, such as a silicon cell. This can be achieved by alloying iodide and bromide anions, but light-induced phase-segregation phenomena are often observed in perovskite films of this kind, with implications for solar cell efficiency. Here, we investigate light-induced phase segregation inside quadruple-cation perovskite material in a complete cell structure and find that the magnitude of this phenomenon is dependent on the operating condition of the solar cell. Under short-circuit and even maximum power point conditions, phase segregation is found to be negligible compared to the magnitude of segregation under open-circuit conditions. In accordance with the finding, perovskite cells based on quadruple-cation perovskite with 1.73 eV bandgap retain 94% of the original efficiency after 12 h operation at the maximum power point, while the cell only retains 82% of the original efficiency after 12 h operation at the open-circuit condition. This result highlights the need to have standard methods including light/dark and bias condition for testing the stability of perovskite solar cells. Additionally, phase segregation is observed when the cell was forward biased at 1.2 V in the dark, which indicates that photoexcitation is not required to induce phase segregation.

  6. Next Generation X-Ray Optics: High-Resolution, Light-Weight, and Low-Cost

    Science.gov (United States)

    Zhang, William W.

    2012-01-01

    X-ray telescopes are essential to the future of x-ray astronomy. In this talk I will describe a comprehensive program to advance the technology for x-ray telescopes well beyond the state of the art represented by the three currently operating missions: Chandra, XMM-Newton, and Suzaku. This program will address the three key issues in making an x-ray telescope: (1) angular resolution, (2) effective area per unit mass, and (3) cost per unit effective area. The objectives of this technology program are (1) in the near term, to enable Explorer-class x-ray missions and an IXO-type mission, and (2) in the long term, to enable a flagship x-ray mission with sub-arcsecond angular resolution and multi-square-meter effective area, at an affordable cost. We pursue two approaches concurrently, emphasizing the first approach in the near term (2-5 years) and the second in the long term (4-10 years). The first approach is precision slumping of borosilicate glass sheets. By design and choice at the outset, this technique makes lightweight and low-cost mirrors. The development program will continue to improve angular resolution, to enable the production of 5-arcsecond x-ray telescopes, to support Explorer-class missions and one or more missions to supersede the original IXO mission. The second approach is precision polishing and light-weighting of single-crystal silicon mirrors. This approach benefits from two recent commercial developments: (1) the inexpensive and abundant availability of large blocks of monocrystalline silicon, and (2) revolutionary advances in deterministic, precision polishing of mirrors. By design and choice at the outset, this technique is capable of producing lightweight mirrors with sub-arcsecond angular resolution. The development program will increase the efficiency and reduce the cost of the polishing and the light-weighting processes, to enable the production of lightweight sub-arcsecond x-ray telescopes. Concurrent with the fabrication of lightweight

  7. Highly efficient tandem polymer solar cells with a photovoltaic response in the visible light range.

    Science.gov (United States)

    Zheng, Zhong; Zhang, Shaoqing; Zhang, Maojie; Zhao, Kang; Ye, Long; Chen, Yu; Yang, Bei; Hou, Jianhui

    2015-02-18

    Highly efficient polymer solar cells with a tandem structure are fabricated by using two excellent photovoltaic polymers and a highly transparent intermediate recombination layer. Power conversion -efficiencies over 10% can be realized with a photovoltaic response within 800 nm. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Quick and Facile Preparation of Visible light-Driven TiO2 Photocatalyst with High Absorption and Photocatalytic Activity

    OpenAIRE

    Yucheng Yang; Ting Zhang; Ling Le; Xuefeng Ruan; Pengfei Fang; Chunxu Pan; Rui Xiong; Jing Shi; Jianhong Wei

    2014-01-01

    Self-doping TiO2 has recently attracted considerable attention for its high photocatalytic activity under visible-light irradiation. However, the literature reported synthetic methods until now were very time-consuming. In this study, we establish a quick and facile method for obtaining self-doping TiO2 with the use of directly treated commercial P25 at a desired temperature for only 5 min through spark plasma sintering technology. With the using of this method, the modified P25 samples exhib...

  9. Parametric analysis of cherenkov light LDF from EAS for high energy gamma rays and nuclei: Ways of practical application

    Directory of Open Access Journals (Sweden)

    Elshoukrofy A.Sh.M.

    2017-01-01

    Full Text Available In this paper we propose a ‘knee-like’ approximation of the lateral distribution of the Cherenkov light from extensive air showers in the energy range 30–3000 TeV and study a possibility of its practical application in high energy ground-based gamma-ray astronomy experiments (in particular, in TAIGA-HiSCORE. The approximation has a very good accuracy for individual showers and can be easily simplified for practical application in the HiSCORE wide angle timing array in the condition of a limited number of triggered stations.

  10. A comparative study of noise in supercontinuum light sources for ultra-high resolution optical coherence tomography

    DEFF Research Database (Denmark)

    Maria J., Sanjuan-Ferrer,; Bravo Gonzalo, Ivan; Bondu, Magalie

    2017-01-01

    Supercontinuum (SC) light is a well-established technology, which finds applications in several domains ranging from chemistry to material science and imaging systems [1-2]. More specifically, its ultra-wide optical bandwidth and high average power make it an ideal tool for Optical Coherence...... illustrate the different noise measurements and their impact on a state of the art UHR-OCT system producing images of skin. The sensitivity of the system was higher than 95 dB, with an axial resolution below 4μm....

  11. Mg 2+-doped GaN nanoparticles as blue-light emitters: a method to avoid sintering at high temperatures.

    Science.gov (United States)

    Mahalingam, Venkataramanan; Sudarsan, Vasanthakumaran; Munusamy, Prabhakaran; van Veggel, Frank C J M; Wang, Rui; Steckl, Andrew J; Raudsepp, Mati

    2008-01-01

    Bright blue-light emission at 410 nm is observed from Mg(2+)-doped GaN nanoparticles prepared by the nitridation of Ga(2)MgO(4) nanoparticles at 950 degrees C. The sintering of these nanoparticles during high-temperature nitridation was prevented by mixing the Ga(2)MgO(4) precursor nanoparticles with La(2)O(3) as an inert matrix before the nitridation process. The Mg(2+)-doped GaN nanoparticles were isolated from the matrix by etching with 10 % nitric acid. The Mg(2+)-doped GaN nanoparticles were characterized by photoluminescence, atomic force microscopy, X-ray diffraction, and IR analyses.

  12. 53% Efficient Red Emissive Carbon Quantum Dots for High Color Rendering and Stable Warm White-Light-Emitting Diodes.

    Science.gov (United States)

    Wang, Zifei; Yuan, Fanglong; Li, Xiaohong; Li, Yunchao; Zhong, Haizheng; Fan, Louzhen; Yang, Shihe

    2017-10-01

    Red emissive carbon quantum dots (R-CQDs) with quantum yield of 53% is successfully prepared. An ultraviolet (UV)-pumped CQD phosphors-based warm white light-emitting diode (WLED) is realized for the first time and achieves a color rendering index of 97. This work provides a new avenue for the exploration of low cost, environment-friendly, and high-performance CQD phosphors-based warm WLEDs. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. A Responsive "Nano String Light" for Highly Efficient mRNA Imaging in Living Cells via Accelerated DNA Cascade Reaction.

    Science.gov (United States)

    Ren, Kewei; Xu, Yifan; Liu, Ying; Yang, Min; Ju, Huangxian

    2017-12-20

    Nonenzymatic DNA catalytic amplification strategies have greatly benefited bioanalysis. However, long period incubation is usually required due to its relatively low reaction rate and efficiency, which limits its in vivo application. Here we design a responsive DNA nano string light (DNSL) by interval hybridization of modified hairpin DNA probe pairs to a DNA nanowire generated by rolling circle amplification and realize accelerated DNA cascade reaction (DCR) for fast and highly efficient mRNA imaging in living cells. Target mRNA initiates interval hybridization of two paired hairpin probes sequentially along the DNA nanowire and results in instant lighting up of the whole DNA nanowire with high signal gain due to the fast opening of all the self-quenched hairpins. The reaction time is about 6.7 times shorter compared with a regular DNA cascade reaction due to the acceleration based on domino effect. The cell delivery is achieved by modifying one of the hairpin probes with folic acid, and this intracellular imaging strategy is verified using human HeLa cells and intracellular survivin mRNA with a series of suppressed expressions as model, which provides a useful platform for fast and highly efficient detection of low-abundance nucleic acids in living cells.

  14. I-TiO2/PVC film with highly photocatalytic antibacterial activity under visible light.

    Science.gov (United States)

    Deng, Weihua; Ning, Shangbo; Lin, Qianying; Zhang, Hualei; Zhou, Tanghua; Lin, Huaxiang; Long, Jinlin; Lin, Qun; Wang, Xuxu

    2016-08-01

    Iodine-modified TiO2(I-TiO2) film were coated on medical-grade PVC material by impregnation-deposition method and subsequently characterized by XRD, SEM, TEM, AFM, DRS and XPS. The photocatalytic anti-bacterial activity of I-TiO2/PVC was investigated both by in vitro anti-bacterial experiments and by clinical study. The results revealed that I-TiO2/PVC exhibit excellent photocatalytic antibacterial activity, which can destroy the propagation of the Escherichia coli and cause the deactivation and death of most E. coli bacteria within 30min visible light illumination. Clinical study on animals showed that I-TiO2 coated on PVC decrease the formation of biofilm on PVC surface in the mechanical ventilation. Furthermore, I-TiO2/PVC can effectively reduce inflammation of tracheal tissue of bam suckling pig and prevents the occurrence of VAP. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Digital Single Lens Reflex Photometry in White Light: a New Concept Tested on Data from the High Amplitude delta Scuti Star V703 Scorpii

    Science.gov (United States)

    Axelsen, R. A.

    2017-06-01

    A novel method of digital single lens reflex (DSLR) photometry is described. It derives non-transformed instrumental magnitudes from white light (green, blue, and red channels of the DSLR sensor combined), and is assessed by comparing the results with non-transformed instrumental magnitudes from the green channel alone, and with green channel magnitudes transformed to the Johnson V standard. The white light data and the non-transformed green channel data allow differential photometry only; true magnitude values cannot be calculated. The same time series images of the high amplitude delta Scuti star V703 Scorpii were processed by all three methods. The light curves from the white light data were almost identical to those from the non-transformed green channel data and to those in V magnitude, but with a slightly greater amplitude for the variable star (from highest peak to lowest trough of the light curve on each night) in the white light curves. There was also an impression, in some areas, of slightly smoother curves from the white light data, implying improved precision. The check star data in white light showed slightly smaller ranges and standard deviations for most nights, and for all nights averaged, than those for the non-transformed green channel data, and for the transformed V magnitude data, implying that the best precision was achieved by using the data in white light. For most of the peaks in the light curve, the times of maximum in white light differed little from those in V magnitude. Fourier analysis using the Lomb-Scargle method revealed identical power spectra and identical discovered frequencies in white light and in V magnitude. DSLR photometry in white light is a valid procedure, at least in those cases where the color indices of the variable and comparison stars differ by only small values. It is considered promising for the timing of maxima and minima of light curves and for Fourier analysis of those stars with more than one period.

  16. Highly durable Cu-based electrodes from a printable nanoparticle mixture ink: flash-light-sintered, kinetically-controlled microstructure.

    Science.gov (United States)

    Park, Hye Jin; Jo, Yejin; Cho, Min Kyung; Young Woo, Jeong; Kim, Dojin; Lee, Su Yeon; Choi, Youngmin; Jeong, Sunho

    2018-02-07

    Recently, printable nanomaterials have drawn tremendous attention for low-cost, large-area electronics applications. In particular, metallic nanoparticles that can facilitate the formation of highly functioning electrodes are indispensable constituent nanomaterials. In this paper, we propose printable mixed inks comprising multicomponent ingredients of Cu, Ni and Cu/Cu10Sn3 core/shell nanoparticles. It is clearly revealed that a characteristic morphology appropriate to highly conductive and durable Cu-based electrodes can be derived easily in a timescale of about 1 ms through an instantaneous flash-light-sintering process, resulting in a resistivity of 49 μΩ cm and normalized resistance variation of around 1 (after 28 days under a harsh environment of 85 °C temperature and 85% humidity). In addition, it is demonstrated that highly functioning electrodes can be formed on thermally vulnerable polyethylene terephthalate (PET) substrates by incorporating an ultrathin optical/thermal plasmonic barrier layer.

  17. High definition versus standard definition white light endoscopy for detecting dysplasia in patients with Barrett's esophagus.

    Science.gov (United States)

    Sami, S S; Subramanian, V; Butt, W M; Bejkar, G; Coleman, J; Mannath, J; Ragunath, K

    2015-01-01

    High-definition endoscopy systems provide superior image resolution. The aim of this study was to assess the utility of high definition compared with standard definition endoscopy system for detecting dysplastic lesions in patients with Barrett's esophagus. A retrospective cohort study of patients with non-dysplastic Barrett's esophagus undergoing routine surveillance was performed. Data were retrieved from the central hospital electronic database. Procedures performed for non-surveillance indications, Barrett's esophagus Prague C0M1 classification with no specialized intestinal metaplasia on histology, patients diagnosed with any dysplasia or cancer on index endoscopy, and procedures using advanced imaging techniques were excluded. Logistic regression models were constructed to estimate adjusted odds ratios and 95% confidence intervals comparing outcomes with standard definition and high-definition systems. The high definition was superior to standard definition system in targeted detection of all dysplastic lesions (odds ratio 3.27, 95% confidence interval 1.27-8.40) as well as overall dysplasia detected on both random and target biopsies (odds ratio 2.36, 95% confidence interval 1.50-3.72). More non-dysplastic lesions were detected with the high-definition system (odds ratio 1.16, 95% confidence interval 1.01-1.33). There was no difference between high definition and standard definition endoscopy in the overall (random and target) high-grade dysplasia or cancers detected (odds ratio 0.93, 95% confidence interval 0.83-1.04). Trainee endoscopists, number of biopsies taken, and male sex were all significantly associated with a higher yield for dysplastic lesions. The use of the high-definition endoscopy system is associated with better targeted detection of any dysplasia during routine Barrett's esophagus surveillance. However, high-definition endoscopy cannot replace random biopsies at present time. © 2014 International Society for Diseases of the Esophagus.

  18. Raman scattering of light and photoinduced control of the parameters of high temperature superconductors

    Science.gov (United States)

    Dovgii, Ia. O.; Kityk, I. V.; Lutsiv, R. V.; Malinich, S. Z.

    1992-01-01

    Results of a comprehensive study of changes in the parameters of high temperature superconductors induced by UV laser irradiation are reported. With reference to results obtained for YBa2Cu3O(6.2) specimens, the possibility of controlling the parameters of high temperature superconductors by exposing then to nitrogen laser radiation at the liquid helium temperature is demonstrated. Good correlation is obtained between structural parameters and Raman modes 115 and 505/cm, which opens the possibility of the remote monitoring of photostructural changes in high temperature superconductors.

  19. Column Store for GWAC: A High-cadence, High-density, Large-scale Astronomical Light Curve Pipeline and Distributed Shared-nothing Database

    Science.gov (United States)

    Wan, Meng; Wu, Chao; Wang, Jing; Qiu, Yulei; Xin, Liping; Mullender, Sjoerd; Mühleisen, Hannes; Scheers, Bart; Zhang, Ying; Nes, Niels; Kersten, Martin; Huang, Yongpan; Deng, Jinsong; Wei, Jianyan

    2016-11-01

    The ground-based wide-angle camera array (GWAC), a part of the SVOM space mission, will search for various types of optical transients by continuously imaging a field of view (FOV) of 5000 degrees2 every 15 s. Each exposure consists of 36 × 4k × 4k pixels, typically resulting in 36 × ˜175,600 extracted sources. For a modern time-domain astronomy project like GWAC, which produces massive amounts of data with a high cadence, it is challenging to search for short timescale transients in both real-time and archived data, and to build long-term light curves for variable sources. Here, we develop a high-cadence, high-density light curve pipeline (HCHDLP) to process the GWAC data in real-time, and design a distributed shared-nothing database to manage the massive amount of archived data which will be used to generate a source catalog with more than 100 billion records during 10 years of operation. First, we develop HCHDLP based on the column-store DBMS of MonetDB, taking advantage of MonetDB’s high performance when applied to massive data processing. To realize the real-time functionality of HCHDLP, we optimize the pipeline in its source association function, including both time and space complexity from outside the database (SQL semantic) and inside (RANGE-JOIN implementation), as well as in its strategy of building complex light curves. The optimized source association function is accelerated by three orders of magnitude. Second, we build a distributed database using a two-level time partitioning strategy via the MERGE TABLE and REMOTE TABLE technology of MonetDB. Intensive tests validate that our database architecture is able to achieve both linear scalability in response time and concurrent access by multiple users. In summary, our studies provide guidance for a solution to GWAC in real-time data processing and management of massive data.

  20. Resveratrol Prevents High Fluence Red Light-Emitting Diode Reactive Oxygen Species-Mediated Photoinhibition of Human Skin Fibroblast Migration.

    Directory of Open Access Journals (Sweden)

    Andrew Mamalis

    Full Text Available Skin fibrosis is a significant medical problem that leads to a functional, aesthetic, and psychosocial impact on quality-of-life. Light-emitting diode-generated 633-nm red light (LED-RL is part of the visible light spectrum that is not known to cause DNA damage and is considered a safe, non-invasive, inexpensive, and portable potential alternative to ultraviolet phototherapy that may change the treatment paradigm of fibrotic skin disease.The goal of our study was to investigate the how reactive oxygen species (ROS free radicals generated by high fluence LED-RL inhibit the migration of skin fibroblasts, the main cell type involved in skin fibrosis. Fibroblast migration speed is increased in skin fibrosis, and we studied cellular migration speed of cultured human skin fibroblasts as a surrogate measure of high fluence LED-RL effect on fibroblast function. To ascertain the inhibitory role of LED-RL generated ROS on migration speed, we hypothesized that resveratrol, a potent antioxidant, could prevent the photoinhibitory effects of high fluence LED-RL on fibroblast migration speed.High fluence LED-RL generated ROS were measured by flow cytometry analysis using dihydrorhodamine (DHR. For purposes of comparison, we assessed the effects of ROS generated by hydrogen peroxide (H2O2 on fibroblast migration speed and the ability of resveratrol, a well known antioxidant, to prevent LED-RL and H2O2 generated ROS-associated changes in fibroblast migration speed. To determine whether resveratrol could prevent the high fluence LED-RL ROS-mediated photoinhibition of human skin fibroblast migration, treated cells were incubated with resveratrol at concentrations of 0.0001% and 0.001% for 24 hours, irradiated with high fluences LED-RL of 480, 640, and 800 J/cm2.High fluence LED-RL increases intracellular fibroblast ROS and decreases fibroblast migration speed. LED-RL at 480, 640 and 800 J/cm2 increased ROS levels to 132.8%, 151.0%, and 158.4% relative to matched